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  • 1.
    Adibekyan, V.
    et al.
    Univ Porto, Inst Astrofis & Ciencias Espaco, CAUP, Rua Estrelas, P-4150762 Oporto, Portugal..
    Delgado-Mena, E.
    Univ Porto, Inst Astrofis & Ciencias Espaco, CAUP, Rua Estrelas, P-4150762 Oporto, Portugal..
    Feltzing, S.
    Lund Observ, Dept Astron & Theoret Phys, Lund, Sweden..
    Gonzalez Hernandez, J. I.
    Inst Astrofis Canarias, Tenerife, Spain.;Univ La Laguna, Dept Astrofis, Tenerife, Spain..
    Hinkel, N. R.
    Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ USA.;Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA..
    Korn, Andreas J.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala Univ, Dept Phys & Astron, Uppsala, Sweden..
    Asplund, M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT, Australia..
    Beck, P. G.
    Univ Paris Diderot, Ctr Saclay, Lab AIM, CEA,DRF,CNRS,IRFU,SAp, Gif Sur Yvette, France..
    Deal, M.
    Univ Montpellier, CNRS, LUPM, UMR 5299, Montpellier, France.;CNRS, IRAP, Toulouse, France..
    Gustafsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. NORDITA, Stockholm, Sweden..
    Honda, S.
    Univ Hyogo, Ctr Astron, Nishi Harima Astron Observ, Sayo, Hyogo, Japan..
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Max Planck Inst Astron, Heidelberg, Germany..
    Nissen, P. E.
    Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Aarhus C, Denmark..
    Spina, L.
    Univ Sao Paulo, Dept Astron IAG, Sao Paulo, Brazil..
    Sun-like stars unlike the Sun: Clues for chemical anomalies of cool stars2017In: Astronomical Notes - Astronomische Nachrichten, ISSN 0004-6337, E-ISSN 1521-3994, Vol. 338, no 4, p. 442-452Article in journal (Refereed)
    Abstract [en]

    We present a summary of the splinter session Sun-like stars unlike the Sun that was held on June 9, 2016, as part of the Cool Stars 19 conference (Uppsala, Sweden), in which the main limitations (in the theory and observations) in the derivation of very precise stellar parameters and chemical abundances of Sun-like stars were discussed. The most important and most debated processes that can produce chemical peculiarities in solar-type stars were outlined and discussed. Finally, in an open discussion between all the participants, we tried to identify new pathways and prospects toward future solutions of the currently open questions.

  • 2. Adén, D.
    et al.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Feltzing, S.
    Grebel, E. K.
    Koch, A.
    Wilkinson, M. I.
    An abundance study of red-giant-branch stars in the Hercules dwarf spheroidal galaxy2011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 525, p. A153-Article in journal (Refereed)
    Abstract [en]

    Context. Dwarf spheroidal galaxies are some of the most metal-poor, and least luminous objects known. Detailed elemental abundance analysis of stars in these faint objects is key to our understanding of star formation and chemical enrichment in the early universe, and may provide useful information on how larger galaxies form. Aims. Our aim is to provide a determination of [Fe/H] and [Ca/H] for confirmed red-giant branch member stars of the Hercules dwarf spheroidal galaxy. Based on this we explore the ages of the prevailing stellar populations in Hercules, and the enrichment history from supernovae. Additionally, we aim to provide a new simple metallicity calibration for Stromgren photometry for metal-poor, red giant branch stars. Methods. High-resolution, multi-fibre spectroscopy and Stromgren photometry are combined to provide as much information on the stars as possible. From this we derive abundances by solving the radiative transfer equations through marcs model atmospheres. Results. We find that the red-giant branch stars of the Hercules dSph galaxy are more metal-poor than estimated in our previous study that was based on photometry alone. From this, we derive a new metallicity calibration for the Stromgren photometry. Additionally, we find an abundance trend such that [Ca/Fe] is higher for more metal-poor stars, and lower for more metal-rich stars, with a spread of about 0.8 dex. The [Ca/Fe] trend suggests an early rapid chemical enrichment through supernovae of type II, followed by a phase of slow star formation dominated by enrichment through supernovae of type Ia. A comparison with isochrones indicates that the red giants in Hercules are older than 10 Gyr.

  • 3.
    Agarwal, Jessica
    et al.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Vincent, J. -B
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hoefner, S.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservat 3, I-35122 Padua, Italy..
    Lamy, P. L.
    Aix Marseille Univ, Lab Astrophys Marseille, CNRS, UMR 7326, 38 Rue Frederic Joliot Curie, F-13388 Marseille 13, France..
    Rodrigo, R.
    CSIC, Ctr Astrobiol, INTA, European Space Agcy,ESAC, POB 78, E-28691 Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Koschny, D.
    European Space Agcy, Res & Sci Support Dept, NL-2201 Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Poland..
    Barucci, M. A.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, LESIA,Observ Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy..
    Boudreault, S.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Cremonese, G.
    INAF Osservat Astron Padova, Vicolo Osservat 5, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, B.
    Jet Prop Lab, M-S 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    Debei, S.
    Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, Via Sommarive 9, I-38123 Trento, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Fornasier, S.
    Univ Paris Diderot, UPMC Univ Paris 06, CNRS, LESIA,Observ Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Fulle, M.
    INAF Osservat Astron Trieste, Via Tiepolo 11, I-34143 Trieste, Italy..
    Gicquel, A.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Groussin, O.
    Aix Marseille Univ, LAM, CNRS, UMR 7326, F-13388 Marseille, France..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Hofmann, M.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hviid, S. F.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Ip, W. -H
    Jorda, L.
    Aix Marseille Univ, LAM, CNRS, UMR 7326, F-13388 Marseille, France..
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Knollenberg, J.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kramm, J. -R
    Kuehrt, E.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kueppers, M.
    ESA ESAC, POB 78, E-28691 Villanueva De La Cananda, Spain..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservat 3, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservat 3, I-35122 Padua, Italy..
    Naletto, G.
    Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy.;CNR IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, Via Gradenigo 6-B, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Shi, X.
    Max Planck Inst Sonnensyst Forsch, Justus Von Liebig Weg 3, D-37077 Gottingen, Germany..
    Thomas, N.
    Univ Bern, Phys Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Acceleration of individual, decimetre-sized aggregates in the lower coma of comet 67P/Churyumov-Gerasimenko2016In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 462, p. S78-S88Article in journal (Refereed)
    Abstract [en]

    We present observations of decimetre-sized, likely ice-containing aggregates ejected from a confined region on the surface of comet 67P/Churyumov-Gerasimenko. The images were obtained with the narrow angle camera of the Optical, Spectroscopic, and Infrared Remote Imaging System on board the Rosetta spacecraft in 2016 January when the comet was at 2 au from the Sun outbound from perihelion. We measure the acceleration of individual aggregates through a 2 h image series. Approximately 50 per cent of the aggregates are accelerated away from the nucleus, and 50 per cent towards it, and likewise towards either horizontal direction. The accelerations are up to one order of magnitude stronger than local gravity, and are most simply explained by the combined effect of gas drag accelerating all aggregates upwards, and the recoil force from asymmetric outgassing, either from rotating aggregates with randomly oriented spin axes and sufficient thermal inertia to shift the temperature maximum away from an aggregate's subsolar region, or from aggregates with variable ice content. At least 10 per cent of the aggregates will escape the gravity field of the nucleus and feed the comet's debris trail, while others may fall back to the surface and contribute to the deposits covering parts of the Northern hemisphere. The rocket force plays a crucial role in pushing these aggregates back towards the surface. Our observations show the future back fall material in the process of ejection, and provide the first direct measurement of the acceleration of aggregates in the innermost coma (<2 km) of a comet, where gas drag is still significant.

  • 4.
    Allende Prieto, C.
    et al.
    Inst Astrofis Canarias, Via Lactea, Tenerife 38205, Spain;Univ La Laguna, Dept Astrofis, E-38206 Tenerife, Spain.
    Koesterke, L.
    Univ Texas Austin, Texas Adv Comp Ctr, Austin, TX 78759 USA.
    Hubeny, I.
    Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA.
    Bautista, M. A.
    Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Nahar, S. N.
    Ohio State Univ, Dept Astron, Columbus, OH 43210 USA.
    A collection of model stellar spectra for spectral types B to early-M2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 618, article id A25Article in journal (Refereed)
    Abstract [en]

    Context: Models of stellar spectra are necessary for interpreting light from individual stars, planets, integrated stellar populations, nebulae, and the interstellar medium.

    Aims: We provide a comprehensive and homogeneous collection of synthetic spectra for a wide range of atmospheric parameters and chemical compositions.

    Methods: We compile atomic and molecular data from the literature. We adopt the largest and most recent set of ATLAS9 model atmospheres, and use the radiative code ASS epsilon T.

    Results: The resulting collection of spectra is made publicly available at medium and high-resolution (R lambda/delta lambda = 10 000, 100 000 and 300 000) spectral grids, which include variations in effective temperature between 3500K and 30 000 K, surface gravity (0 <= log g <= 5), and metallicity (-5 <= [Fe/H] <= +0 : 5), spanning the wavelength interval 120-6500 nm. A second set of denser grids with additional dimensions, [alpha/ Fe] and micro-turbulence, are also provided (covering 200-2500 nm). We compare models with observations for a few representative cases.

  • 5.
    Amarsi, A. M.
    et al.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Asplund, M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Collet, R.
    Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
    Zatsarinny, O.
    Drake Univ, Dept Phys & Astron, Des Moines, IA 50311 USA.
    Inelastic O plus H collisions and the O I 777 nm solar centre-to-limb variation2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id A89Article in journal (Refereed)
    Abstract [en]

    The O I 777 nm triplet is a key diagnostic of oxygen abundances in the atmospheres of FGK-type stars; however, it is sensitive to departures from local thermodynamic equilibrium (LTE). The accuracy of non-LTE line formation calculations has hitherto been limited by errors in the inelastic O+H collisional rate coefficients; several recent studies have used the Drawin recipe, albeit with a correction factor S-H that is calibrated to the solar centre-to-limb variation of the triplet. We present a new model oxygen atom that incorporates inelastic O+H collisional rate coefficients using an asymptotic two-electron model based on linear combinations of atomic orbitals, combined with a free electron model based on the impulse approximation. Using a 3D hydrodynamic STAGGER model solar atmosphere and 3D non-LTE line formation calculations, we demonstrate that this physically motivated approach is able to reproduce the solar centre-to-limb variation of the triplet to 0.02 dex, without any calibration of the inelastic collisional rate coefficients or other free parameters. We infer log epsilon(O) = 8.69 +/- 0.03 from the triplet alone, strengthening the case for a low solar oxygen abundance.

  • 6.
    Amarsi, A. M.
    et al.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Nordlander, T.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia;ARC Ctr Excellence All Sky Astrophys 3 Dimens AST, Canberra, ACT, Australia.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Asplund, M.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Collet, R.
    Aarhus Univ, Dept Phys & Astron, Stellar Astrophys Ctr, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
    Lind, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Effective temperature determinations of late-type stars based on 3D non-LTE Balmer line formation2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 615, article id A139Article in journal (Refereed)
    Abstract [en]

    Hydrogen Balmer lines are commonly used as spectroscopic effective temperature diagnostics of late-type stars. However, reliable inferences require accurate model spectra, and the absolute accuracy of classical methods that are based on one-dimensional (1D) hydrostatic model atmospheres and local thermodynamic equilibrium (LTE) is still unclear. To investigate this, we carry out 3D non-LTE calculations for the Balmer lines, performed, for the first time, over an extensive grid of 3D hydrodynamic STAGGER model atmospheres. For H alpha, H beta, and H gamma we find significant 1D non-LTE versus 3D non-LTE differences (3D effects): the outer wings tend to be stronger in 3D models, particularly for H gamma, while the inner wings can be weaker in 3D models, particularly for H alpha. For H alpha, we also find significant 3D LTE versus 3D non-LTE differences (non-LTE effects): in warmer stars (T-eff approximate to 6500 K) the inner wings tend to be weaker in non-LTE models, while at lower effective temperatures (T-eff approximate to 4500 K) the inner wings can be stronger in non-LTE models; the non-LTE effects are more severe at lower metallicities. We test our 3D non-LTE models against observations of well-studied benchmark stars. For the Sun, we infer concordant effective temperatures from H alpha, H beta, and H gamma; however the value is too low by around 50 K which could signal residual modelling shortcomings. For other benchmark stars, our 3D non-LTE models generally reproduce the effective temperatures to within 1 sigma uncertainties. For H alpha, the absolute 3D effects and non-LTE effects can separately reach around 100 K, in terms of inferred effective temperatures. For metal-poor turn-off stars, 1D LTE models of H alpha can underestimate effective temperatures by around 150 K. Our 3D non-LTE model spectra are publicly available, and can be used for more reliable spectroscopic effective temperature determinations.

  • 7.
    Andrae, Rene
    et al.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Fouesneau, Morgan
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Creevey, Orlagh
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Ordenovic, Christophe
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Mary, Nicolas
    Thales Serv, 290 Allee Lac, F-31670 Labege, France.
    Burlacu, Alexandru
    Telespazio France, 26 Ave Jean Francois Champollion, F-31100 Toulouse, France.
    Chaoul, Laurence
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Jean-Antoine-Piccolo, Anne
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Kordopatis, Georges
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Lebreton, Yveline
    Univ Rennes 1, Inst Phys Rennes, CNRS, UMR 6251, F-35042 Rennes, France;Univ Paris Diderot, LESIA, Observ Paris, PSL Res Univ,CNRS,UMR 8109,Univ Pierre & Marie Cu, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Panem, Chantal
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Pichon, Bernard
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Thevenin, Frederic
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Walmsley, Gavin
    Ctr Natl Etud Spatiales, 18 Ave Edouard Belin, F-31401 Toulouse, France.
    Bailer-Jones, Coryn A. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    First stellar parameters from Apsis2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id A8Article in journal (Refereed)
    Abstract [en]

    The second Gaia data release (Gaia DR2) contains, beyond the astrometry, three-band photometry for 1.38 billion sources. One band is the G band, the other two were obtained by integrating the Gaia prism spectra (BP and RP). We have used these three broad photometric bands to infer stellar effective temperatures, T-eff, for all sources brighter than G = 17 mag with T-eff in the range 3000-10 000K (some 161 million sources). Using in addition the parallaxes, we infer the line-of-sight extinction, A(G), and the reddening, E(BP-RP), for 88 million sources. Together with a bolometric correction we derive luminosity and radius for 77 million sources. These quantities as well as their estimated uncertainties are part of Gaia DR2. Here we describe the procedures by which these quantities were obtained, including the underlying assumptions, comparison with literature estimates, and the limitations of our results. Typical accuracies are of order 324K (T-eff), 0.46 mag (A(G)), 0.23 mag (E(BP-RP)), 15% (luminosity), and 10% (radius). Being based on only a small number of observable quantities and limited training data, our results are necessarily subject to some extreme assumptions that can lead to strong systematics in some cases (not included in the aforementioned accuracy estimates). One aspect is the non-negativity contraint of our estimates, in particular extinction, which we discuss. Yet in several regions of parameter space our results show very good performance, for example for red clump stars and solar analogues. Large uncertainties render the extinctions less useful at the individual star level, but they show good performance for ensemble estimates. We identify regimes in which our parameters should and should not be used and we define a "clean" sample. Despite the limitations, this is the largest catalogue of uniformly-inferred stellar parameters to date. More precise and detailed astrophysical parameters based on the full BP/RP spectrophotometry are planned as part of the third Gaia data release.

  • 8.
    Aronson, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Bladh, S.
    Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Modelling polarized light from dust shells surrounding asymptotic giant branch stars2017In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 603, article id A116Article in journal (Refereed)
    Abstract [en]

    Context. Winds of asymptotic giant branch (AGB) stars are commonly assumed to be driven by radiative acceleration of dust grains. For M-type AGB stars, the nature of the wind-driving dust species has been a matter of intense debate. A proposed source of the radiation pressure triggering the outflows is photon scattering on Fe-free silicate grains. This wind-driving mechanism requires grain radii of about 0.1-1 micron in order to make the dust particles efficient at scattering radiation around the stellar flux maximum. Grain size is therefore an important parameter for understanding the physics behind the winds of M-type AGB stars. Aims. We seek to investigate the diagnostic potential of scattered polarized light for determining dust grain sizes. Methods. We have developed a new tool for computing synthetic images of scattered light in dust and gas shells around AGB stars, which can be applied to detailed models of dynamical atmospheres and dust-driven winds. Results. We present maps of polarized light using dynamical models computed with the DARWIN code. The synthetic images clearly show that the intensity of the polarized light, the position of the inner edge of the dust shell, and the size of the dust grains near the inner edge are all changing with the luminosity phase. Non-spherical structures in the dust shells can also have an impact on the polarized light. We simulate this effect by combining different pulsation phases into a single 3D structure before computing synthetic images. An asymmetry of the circumstellar envelope can create a net polarization, which can be used as diagnostics for the grain size. The ratio between the size of the scattering particles and the observed wavelength determines at what wavelengths net polarization switches direction. If observed, this can be used to constrain average particle sizes.

  • 9. Arroyo-Torres, B.
    et al.
    Wittkowski, M.
    Chiavassa, A.
    Scholz, M.
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Marcaide, J. M.
    Hauschildt, P. H.
    Wood, P. R.
    Abellan, F. J.
    What causes the large extensions of red supergiant atmospheres?: Comparisons of interferometric observations with 1D hydrostatic, 3D convection, and 1D pulsating model atmospheres2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 575, article id A50Article in journal (Refereed)
    Abstract [en]

    Aims. This research has two main goals. First, we present the atmospheric structure and the fundamental parameters of three red supergiants (RSGs), increasing the sample of RSGs observed by near-infrared spectro-interferometry. Additionally, we test possible mechanisms that may explain the large observed atmospheric extensions of RSGs. Methods. We carried out spectro-interferometric observations of the.RSGs V602 Car, EID 95687, and EID 183589 in the near-infrared K-band (1.92-2.47 mu m) with the VLTI/AMBER instrument at medium spectral resolution (R similar to 1500). To categorize and comprehend the extended atmospheres, we compared our observational results to predictions by available hydrostatic PHOENIX, available 3D convection, and new 1D self-excited pulsation models of RSGs. Results. Our near-infrared flux spectra of V602 Car, HD 95687, and HD 183589 are well reproduced by the PHOENIX model atmospheres. The continuum visibility values are consistent with a limb-darkened disk as predicted by the PHOENIX models, allowing us to determine the angular diameter and the fundamental parameters of our sources. Nonetheless, in the case of V602 Car and HD 95686, the PHOENIX model visibilities do not predict the large observed extensions of molecular layers, most remarkably in the CO bands. Likewise, the 3D convection models and the ID pulsation models with typical parameters of RSGs lead to compact atmospheric structures as well, which are similar to the structure of the hydrostatic PHOENIX models. They can also not explain the observed decreases in the visibilities and thus the large atmospheric molecular extensions. The full sample of our RSGs indicates increasing observed atmospheric extensions with increasing luminosity and decreasing surface gravity, and no correlation with effective temperature or variability amplitude. Conclusions. The location of our RSG sources in the Hertzsprung-Russell diagram is contirm.ed to be consistent with the red limits of recent evolutionary tracks. The observed extensions of the atmospheric layers of our sample of RSGs are comparable to those of Mira stars. This phenomenon is not predicted by any of the considered model atmospheres including as 311) convection and new 1D pulsation models of.RSGs. This confirms that neither convection nor pulsation alone can levitate the molecular atmospheres of.RSGs. Our observed correlation of atmospheric extension with luminosity supports a scenario of radiative acceleration on Doppler-shifted molecular lines.

  • 10.
    Arroyo-Torres, B.
    et al.
    Univ Valencia, Dept Astron & Astrofis, E-46100 Burjassot, Spain..
    Wittkowski, M.
    ESO, Garching, Germany..
    Marcaide, J. M.
    Univ Valencia, Dept Astron & Astrofis, E-46100 Burjassot, Spain.;Donostia Int Phys Ctr, Donostia San Sebastian, Spain..
    Abellan, F. J.
    Univ Valencia, Dept Astron & Astrofis, E-46100 Burjassot, Spain..
    Chiavassa, A.
    Univ Nice Sophia Antipolis, Lab Lagrange, CNRS, Observ Cote Azur, Sophia Anitpolis, France..
    Fabregat, J.
    Univ Valencia, Astron Observ, E-46003 Valencia, Spain..
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Guirado, J. C.
    Univ Valencia, Dept Astron & Astrofis, E-46100 Burjassot, Spain.;Univ Valencia, Astron Observ, E-46003 Valencia, Spain..
    Hauschildt, P. H.
    Hamburger Sternwarte, Hamburg, Germany..
    Marti-Vidal, I.
    Chalmers, Onsala Space Observ, Gothenburg, Sweden..
    Quirrenbach, A.
    Heidelberg Univ, Zentrum Astron, Landessternwarte, D-69115 Heidelberg, Germany..
    Scholz, M.
    Heidelberg Univ, Zentrum Astron, Inst Theoret Astrophys, D-69115 Heidelberg, Germany.;Univ Sydney, Sch Phys, Sydney Inst Astron, Sydney, NSW 2006, Australia..
    Wood, P. R.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT, Australia..
    VLTI/AMBER Studies of the Atmospheric Structure and Fundamental Parameters of Red Giant and Supergiant Stars2015In: WHY GALAXIES CARE ABOUT AGB STARS III: A CLOSER LOOK IN SPACE AND TIME, ASTRONOMICAL SOC PACIFIC , 2015, Vol. 497, p. 91-96Conference paper (Other academic)
    Abstract [en]

    We present recent near-IR interferometric studies of red giant and super giant stars, which are aimed at obtaining information on the structure of the atmospheric layers and constraining the fundamental parameters of these objects. The observed visibilities of six red supergiants (RSGs), and also of one of the five red giants observed, indicate large extensions of the molecular layers, as previously observed for Mira stars. These extensions are not predicted by hydrostatic PHOENIX model atmospheres, hydrodynamical (RED) simulations of stellar convection, or self-excited pulsation models. All these models based on parameters of RSGs lead to atmospheric structures that are too compact compared to our observations. We discuss how alternative processes might explain the atmospheric extensions for these objects. As the continuum appears to be largely free of contamination by molecular layers, we can estimate reliable Rosseland angular radii for our stars. Together with distances and bolometric fluxes, we estimate the effective temperatures and luminosities of our targets, locate them in the HR diagram, and compare their positions to recent evolutionary tracks.

  • 11.
    Attree, N.
    et al.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Groussin, O.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Jorda, L.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Nebouy, D.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Thomas, N.
    Univ Bern, Physikal Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Brouet, Y.
    Univ Bern, Physikal Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Kuehrt, E.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Preusker, F.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Scholten, F.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Knollenberg, J.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Hartogh, P.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Barbieri, C.
    Padova Univ, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Lamy, P.
    Aix Marseille Univ, CNRS, LAM, Marseille, France..
    Rodrigo, R.
    INTA CSIC, Ctr Astrobiol, Madrid 28691, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Koschny, D.
    ESA, Sci Support Off, NL-2201 Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Bartycka 18A, PL-00716 Warsaw, Poland..
    Keller, H. U.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany.;TU Braunschweig, Inst Geophys & Extraterrestrial Phys, D-38106 Braunschweig, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Auger, A. -T
    Barucci, M. A.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Obs Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Bodewits, D.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Boudreault, S.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Cremonese, G.
    Da Deppo, V.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, B.
    Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Debei, S.
    Univ Padua, Dept Ind Engn, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, UNITN, Via Mesiano 77, I-38100 Trento, Italy..
    Deller, J.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    El-Maarry, M. R.
    Univ Bern, Physikal Inst, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Fornasier, S.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Obs Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Fulle, M.
    INAF Osservatorio Astronom, Via Tiepolo 11, I-34143 Trieste, Italy..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astronomia S-N, Granada 18008, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Hviid, S.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Ip, W. -H
    Kovacs, G.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Kramm, J. R.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Kueppers, M.
    ESA, European Space Astron Ctr, Operat Dept, POB 78, Madrid 28691, Spain..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, Glorieta Astronomia S-N, Granada 18008, Spain..
    Lazzarin, M.
    Moreno, J. J. Lopez
    CSIC, Inst Astrofis Andalucia, Glorieta Astronomia S-N, Granada 18008, Spain..
    Lowry, S.
    Univ Kent, Sch Phys Sci SEPnet, Ctr Astrophys & Planetary Sci, Canterbury CT2 7NH, Kent, England..
    Marchi, S.
    Southwest Res Inst, 1050 Walnut St, Boulder, CO 80302 USA..
    Marzari, F.
    Padova Univ, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Mottola, S.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Naletto, G.
    Padova Univ, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy.;Univ Padua, Ctr Ateneo Studi Attivita Spaziali Giuseppe Colom, Via Venezia 15, I-35131 Padua, Italy.;CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Oklay, N.
    Inst Planetary Res DLR, Rutherfordstr 2, Berlin, Germany..
    Pajola, M.
    NASA, Ames Res Ctr, Moffett Field, CA 94035 USA..
    Toth, I.
    MTA CSFK Konkoly Observ, Konkoly Thege M Ut 15-17, H-1121 Budapest, Hungary..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Shi, X.
    Tensile strength of 67P/Churyumov-Gerasimenko nucleus material from overhangs2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 611, article id A33Article in journal (Refereed)
    Abstract [en]

    We directly measured twenty overhanging cliffs on the surface of comet 67P/Churyumov-Gerasimenko extracted from the latest shape model and estimated the minimum tensile strengths needed to support them against collapse under the comet's gravity. We find extremely low strengths of around 1 Pa or less (1 to 5 Pa, when scaled to a metre length). The presence of eroded material at the base of most overhangs, as well as the observed collapse of two features and the implied previous collapse of another, suggests that they are prone to failure and that the true material strengths are close to these lower limits (although we only consider static stresses and not dynamic stress from, for example, cometary activity). Thus, a tensile strength of a few pascals is a good approximation for the tensile strength of the 67P nucleus material, which is in agreement with previous work. We find no particular trends in overhang properties either with size over the similar to 10-100 m range studied here or location on the nucleus. There are no obvious differences, in terms of strength, height or evidence of collapse, between the populations of overhangs on the two cometary lobes, suggesting that 67P is relatively homogenous in terms of tensile strength. Low material strengths are supportive of cometary formation as a primordial rubble pile or by collisional fragmentation of a small body (tens of km).

  • 12. Auger, A. -T
    et al.
    Groussin, O.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Jorda, L.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Bouley, S.
    Univ Paris 11, Lab GEOPS, Geosci Paris Sud, F-91405 Orsay, France.;Inst Mecan Celeste & Calcul Ephemerides, UMR 8028, F-75014 Paris, France..
    Gaskell, R.
    Planetary Sci Inst, Tucson, AZ 85719 USA..
    Lamy, P. L.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Capanna, C.
    Aix Marseille Univ, CNRS, UMR 7326, LAM, F-13388 Marseille, France..
    Thomas, N.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Pommerol, A.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Rodrigo, R.
    Ctr Astrobiol INTA CSIC, Madrid 28691, Spain.;Int Space Sci Inst, CH-3012 Bern, Switzerland..
    Koschny, D.
    European Space Agcy, Sci Support Off, NL-2201 Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Keller, H. U.
    Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Agarwal, J.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Barucci, M. A.
    Univ Paris Diderot, Univ Paris 06, Observ Paris, LESIA,CNRS, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, CISAS, I-35100 Padua, Italy..
    Cremonese, G.
    Univ Padua, Dept Mech Engn, I-35131 Padua, Italy..
    Da Deppo, V.
    CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy..
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Debei, S.
    Univ Padua, Dept Mech Engn, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, UNITN, I-38100 Trento, Italy..
    El-Maarry, M. R.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Fornasier, S.
    Univ Paris Diderot, Univ Paris 06, Observ Paris, LESIA,CNRS, F-92195 Meudon, France..
    Fulle, M.
    Osserv Astron Trieste, INAF, I-34143 Trieste, Italy..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Hviid, S.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Ip, W. -H
    Knollenberg, J.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kramm, J. -R
    Kuehrt, E.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kueppers, M.
    European Space Astron Ctr ESA, Operat Dept, Madrid 28691, Spain..
    La Forgia, F.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Marchi, S.
    Southwest Res Inst, Boulder, CO 80302 USA..
    Marzari, F.
    Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy..
    Massironi, M.
    Osserv Astron Padova, INAF, I-35121 Padua, Italy.;Univ Padua, Ctr Ateneo Studi & Attivita Spaziali Giuseppe Col, I-35131 Padua, Italy..
    Michalik, H.
    Tech Univ Carolo Wilhelmina Braunschweig, Inst Datentech & Kommunikat Netze, D-38106 Braunschweig, Germany..
    Naletto, G.
    Univ Padua, CISAS, I-35100 Padua, Italy.;CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Pajola, M.
    Univ Padua, Ctr Ateneo Studi & Attivita Spaziali Giuseppe Col, I-35131 Padua, Italy..
    Sabau, L.
    Inst Nacl Tecn Aeroesp, Madrid 28850, Spain..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Wenzel, K. -P
    Geomorphology of the Imhotep region on comet 67P/Churyumov-Gerasimenko from OSIRIS observations2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 583, article id A35Article in journal (Refereed)
    Abstract [en]

    Context. Since August 2014, the OSIRIS Narrow Angle Camera (NAC) onboard the Rosetta spacecraft has acquired high spatial resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko, down to the decimeter scale. This paper focuses on the Imhotep region, located on the largest lobe of the nucleus, near the equator. Aims. We map, inventory, and describe the geomorphology of the Imhotep region. We propose and discuss some processes to explain the formation and ongoing evolution of this region. Methods. We used OSIRIS NAC images, gravitational heights and slopes, and digital terrain models to map and measure the morphologies of Imhotep. Results. The Imhotep region presents a wide variety of terrains and morphologies: smooth and rocky terrains, bright areas, linear features, roundish features, and boulders. Gravity processes such as mass wasting and collapse play a significant role in the geomorphological evolution of this region. Cometary processes initiate erosion and are responsible for the formation of degassing conduits that are revealed by elevated roundish features on the surface. We also propose a scenario for the formation and evolution of the Imhotep region; this implies the presence of large primordial voids inside the nucleus, resulting from its formation process.

  • 13.
    Babusiaux, C.
    et al.
    Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    van Leeuwen, F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Barstow, M. A.
    Univ Leicester, Dept Phys & Astron, Leicester Inst Space & Earth Observat, Univ Rd, Leicester LE1 7RH, Leics, England.
    Jordi, C.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Vallenari, A.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bossini, D.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bressan, A.
    SISSA, Via Bonomea 265, I-34136 Trieste, Italy.
    Cantat-Gaudin, T.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    van Leeuwen, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Brown, A. G. A.
    Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Prusti, T.
    ESA ESTEC, Directorate Sci, Sci Support Off, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    de Bruijne, J. H. J.
    ESA ESTEC, Directorate Sci, Sci Support Off, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    Bailer-Jones, C. A. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Biermann, M.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Evans, D. W.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Eyer, L.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Jansen, F.
    ESA ESTEC, Directorate Sci, Operat Dept, Miss Operat Div, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    Klioner, S. A.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Lammers, U.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Lindegren, L.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Luri, X.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Mignard, F.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Panem, C.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Pourbaix, D.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium;FRS FNRS, Rue Egmont 5, B-1000 Brussels, Belgium.
    Randich, S.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Sartoretti, P.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Siddiqui, H. I.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Soubiran, C.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Walton, N. A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Arenou, F.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Bastian, U.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Cropper, M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Drimmel, R.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Katz, D.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Lattanzi, M. G.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Bakker, J.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Cacciari, C.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Castaneda, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Chaoul, L.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Cheek, N.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    De Angeli, F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Fabricius, C.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Guerra, R.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Holl, B.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Masana, E.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Messineo, R.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Mowlavi, N.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Nienartowicz, K.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Panuzzo, P.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Portell, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Riello, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Seabroke, G. M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Tanga, P.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Thevenin, F.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Gracia-Abril, G.
    ESAC, Gaia DPAC Project Off, Camino Bajo Castillo S-N, Madrid 28692, Spain;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Comoretto, G.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Garcia-Reinaldos, M.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Teyssier, D.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Altmann, M.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany;Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Andrae, R.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Audard, M.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Bellas-Velidis, I.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Benson, K.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Berthier, J.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Blomme, R.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Burgess, P.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Busso, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Carry, B.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France;Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Cellino, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Clementini, G.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Clotet, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Creevey, O.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Davidson, M.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    De Ridder, J.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Delchambre, L.
    Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Dell'Oro, A.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Ducourant, C.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Fernandez-Hernandez, J.
    ESA ESAC, ATG Europe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Fouesneau, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Fremat, Y.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Galluccio, L.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Garcia-Torres, M.
    Univ Pablo Olavide, Area Lenguajes Sistemas Informat, Ctr Utrera,Km 1, Seville 41013, Spain.
    Gonzalez-Nunez, J.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain;Univ Vigo, ETSE Telecomun, Campus Lagoas Marcosende, Vigo 36310, Spain.
    Gonzalez-Vidal, J. J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Gosset, E.
    FRS FNRS, Rue Egmont 5, B-1000 Brussels, Belgium;Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Guy, L. P.
    Large Synopt Survey Telescope, 950 N Cherry Ave, Tucson, AZ 85719 USA;Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Halbwachs, J. -L
    Hambly, N. C.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Harrison, D. L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Cambridge, Kavli Inst Cosmol, Madingley Rd, Cambride CB3 0HA, England.
    Hernandez, J.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Hestroffer, D.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Hodgkin, S. T.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Hutton, A.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Jasniewicz, G.
    Univ Montpellier, Lab Univ & Particules Montpellier, Pl Eugene Bataillon,CC72, F-34095 Montpellier 05, France.
    Jean-Antoine-Piccolo, A.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Jordan, S.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Krone-Martins, A.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Lanzafame, A. C.
    Univ Catania, Dipartimento Fis & Astron, Sez Astrofis, Via S Sofia 78, I-95123 Catania, Italy;INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Lebzelter, T.
    Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
    Loeffler, W.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Manteiga, M.
    Univ A Coruna, CITIC Astron & Astrophys, Campus Elvina S-N, La Coruna 15071, Spain;Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Marrese, P. M.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Martin-Fleitas, J. M.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Moitinho, A.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Mora, A.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Muinonen, K.
    Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland;Finnish Geospatial Res Inst FGI, Geodeetinrinne 2, Masala 02430, Finland.
    Osinde, J.
    ESA ESAC, Isdefe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Pancino, E.
    ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy;INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Pauwels, T.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Petit, J. -M
    Recio-Blanco, A.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Richards, P. J.
    Rutherford Appleton Lab, STFC, Harwell OX11 0QX, Didcot, England.
    Rimoldini, L.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Robin, A. C.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Sarro, L. M.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Siopis, C.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium.
    Smith, M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Sozzetti, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Sueveges, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Torra, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    van Reeven, W.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Abbas, U.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Abreu Aramburu, A.
    ESA ESAC, Elecnor Deimos Space, Camino Bajo Castillo S-N, Madrid 28692, Spain;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland;Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Accart, S.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Aerts, C.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Altavilla, G.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy;INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Alvarez, M. A.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Alvarez, R.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Alves, J.
    Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
    Anderson, R. I.
    European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching, Germany;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Andrei, A. H.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France;ON MCTI BR, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, Brazil;OV UFRJ BR, Ladeira Pedro Antonio 43, BR-20080090 Rio De Janeiro, Brazil.
    Anglada Varela, E.
    ESA ESAC, ATG Europe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Antiche, E.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Antoja, T.
    ESA ESTEC, Directorate Sci, Sci Support Off, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Arcay, B.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Astraatmadja, T. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Carnegie Inst Sci, Dept Terr Magnetism, 5241 Broad Branch Rd,NW, Washington, DC 20015 USA.
    Bach, N.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Baker, S. G.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Balaguer-Nunez, L.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Balm, P.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Barache, C.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Barata, C.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Barbato, D.
    Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin, Italy;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Barblan, F.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Barrado, D.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Barros, M.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Bartholome Munoz, S.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Bassilana, J. -L
    Becciani, U.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Bellazzini, M.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Berihuete, A.
    Univ Cadiz, Dept Estadist, Calle Republica Arabe Saharawi S-N, Puerto Real 11510, Spain;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Bertones, S.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Bern Univ, Astron Inst, Sidlerstr 5, CH-3012 Bern, Switzerland.
    Bianchi, L.
    EURIX Srl, Corso Vittorio Emanuele 2 61, I-10128 Turin, Italy.
    Bienayme, O.
    Univ Strasbourg, CNRS, Observ Astron Strasbourg, UMR 7550, 11 Rue Univ, F-67000 Strasbourg, France.
    Blanco-Cuaresma, S.
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA;Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Boch, T.
    Univ Strasbourg, CNRS, Observ Astron Strasbourg, UMR 7550, 11 Rue Univ, F-67000 Strasbourg, France.
    Boeche, C.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bombrun, A.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Borrachero, R.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Bouquillon, S.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Bourda, G.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Bragaglia, A.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Bramante, L.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Breddels, M. A.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Brouillet, N.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Bruesemeister, T.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Brugaletta, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Bucciarelli, B.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Burlacu, A.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Busonero, D.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Butkevich, A. G.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Buzzi, R.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Caffau, E.
    Cancelliere, R.
    Univ Turin, Dept Comp Sci, Corso Svizzera 185, I-10149 Turin, Italy.
    Cannizzaro, G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON, Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Carballo, R.
    Univ Cantabria, Dept Matemat Aplicada & Ciencias Comp, ETS Ingenieros Caminos Canales & Puertos, Avda Castros S-N, E-39005 Santander, Spain.
    Carlucci, T.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Carrasco, J. M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Casamiquela, L.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Castellani, M.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy.
    Castro-Ginard, A.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Charlot, P.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Chemin, L.
    Univ Antofagasta, Unidad Astron, Ave Angamos 601, Antofagasta 1270300, Chile.
    Chiavassa, A.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Cocozza, G.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Costigan, G.
    Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Cowell, S.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Crifo, F.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Crosta, M.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Crowley, C.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Cuypers, J.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Dafonte, C.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Damerdji, Y.
    CRAAG, Route Observ Bp 63, Algiers 16340, Algeria;Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Dapergolas, A.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    David, P.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    David, M.
    Univ Antwerp, Onderzoeksgroep Toegepaste Wiskunde, Middelheimlaan 1, B-2020 Antwerp, Belgium.
    de laverny, P.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    De Luise, F.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    De March, R.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    de Martino, D.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    de Souza, R.
    Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226,Cidade Univ, BR-05508900 Sao Paulo, Brazil.
    de Torres, A.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Debosscher, J.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    del Pozo, E.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Delbo, M.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Delgado, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Delgado, H. E.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Diakite, S.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Diener, C.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Distefano, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Dolding, C.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Drazinos, P.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Duran, J.
    ESA ESAC, Isdefe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Edvardsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Enke, H.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Esquej, P.
    ESA ESAC, RHEA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Bontemps, G. Eynard
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Fabre, C.
    CNES Ctr Spatial Toulouse, ATOS, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Fabrizio, M.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Faigler, S.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    Falcao, A. J.
    UNINOVA CTS, Campus FCT UNL, P-2829516 Caparica, Portugal.
    Casas, M. Farras
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Federici, L.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Fedorets, G.
    Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland.
    Fernique, P.
    Univ Strasbourg, CNRS, Observ Astron Strasbourg, UMR 7550, 11 Rue Univ, F-67000 Strasbourg, France.
    Figueras, F.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Filippi, F.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Findeisen, K.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Fonti, A.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Fraile, E.
    ESA ESAC, RHEA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Fraser, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Coll Dublin, Sch Phys, OBrien Ctr Sci North, Dublin 4, Ireland.
    Frezouls, B.
    Univ Antwerp, Onderzoeksgroep Toegepaste Wiskunde, Middelheimlaan 1, B-2020 Antwerp, Belgium.
    Gai, M.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Galleti, S.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Garabato, D.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Garcia-Sedano, F.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Garofalo, A.
    Univ Bologna, Dipartimento Fis & Astron, Via Piero Gobetti 93-2, I-40129 Bologna, Italy;INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Garralda, N.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Gavel, Alvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Gavras, P.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece;Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Gerssen, J.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Geyer, R.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Giacobbe, P.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Gilmore, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Girona, S.
    Ctr Nacl Super Comp, Barcelona Supercomputing Ctr, C Jordi Girona 29,Ed Nexus 2, Barcelona 08034, Spain.
    Giuffrida, G.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Glass, F.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Gomes, M.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Granvik, M.
    Lulea Univ Technol, Dept Comp Sci Elect & Space Engn, Box 848, S-98128 Kiruna, Sweden;Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland.
    Gueguen, A.
    Max Planck Inst Extraterrestrial Phys, High Energy Grp, Giessenbachstr, D-85741 Garching, Germany;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Guerrier, A.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Guiraud, J.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Gutierrez-Sanchez, R.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Haigron, R.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Hatzidimitriou, D.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece;Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Hauser, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Haywood, M.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Helmi, A.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Heu, J.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Hilger, T.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Hobbs, D.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Hofmann, W.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Holland, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Huckle, H. E.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Hypki, A.
    Adam Mickiewicz Univ, Astron Observ Inst, Fac Phys, Sloneczna 36, PL-60286 Poznan, Poland;Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Icardi, V.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Janssen, K.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Jevardat de Fombelle, G.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Jonker, P. G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON, Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Juhasz, A. L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary;Eotvos Lorand Univ, Egyet Ter 1-3, H-1053 Budapest, Hungary.
    Julbe, F.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Karampelas, A.
    Amer Community Sch Athens, 129 Aghias Paraskevis Ave & Kazantzaki St, Athens 15234, Greece;Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Kewley, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Klar, J.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Kochoska, A.
    Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia;Villanova Univ, Dept Astrophys & Planetary Sci, 800 Lancaster Ave, Villanova, PA 19085 USA.
    Kohley, R.
    ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Kolenberg, K.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium;Univ Antwerp, Phys Dept, Groenenborgerlaan 171, B-2020 Antwerp, Belgium;Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA.
    Kontizas, M.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Kontizas, E.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Koposov, S. E.
    Carnegie Mellon Univ, McWilliams Ctr Cosmol, Dept Phys, 5000 Forbes Ave, Pittsburgh, PA 15213 USA;Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Kordopatis, G.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Kostrzewa-Rutkowska, Z.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON, Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Koubsky, P.
    Acad Sci Czech Republ, Astron Inst, Fricova 298, Ondrejov 25165, Czech Republic.
    Lambert, S.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Lanza, A. F.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Lasne, Y.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Lavigne, J. -B
    Le Fustec, Y.
    CNES Ctr Spatial Toulouse, Telespazio, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Le Poncin-Lafitte, C.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Lebreton, Y.
    Univ Rennes 1, Inst Phys Rennes, F-35042 Rennes, France;Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Leccia, S.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Leclerc, N.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Lecoeur-Taibi, I.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Lenhardt, H.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Leroux, F.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Liao, S.
    Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China.
    Licata, E.
    EURIX Srl, Corso Vittorio Emanuele 2 61, I-10128 Turin, Italy.
    Lindstrom, H. E. P.
    Univ Copenhagen, Niels Bohr Inst, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark;DXC Technol, Retortvej 8, DK-2500 Valby, Denmark.
    Lister, T. A.
    Las Cumbres Observ, 6740 Cortona Dr Suite, Goleta, CA 93117 USA.
    Livanou, E.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Lobel, A.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Lopez, M.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Managau, S.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Mann, R. G.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Mantelet, G.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Marchal, O.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Marchant, J. M.
    Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England.
    Marconi, M.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Marinoni, S.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Marschalko, G.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary;Univ Szeged, Baja Observ, Szegedi Ut II 70, H-6500 Baja, Hungary.
    Marshall, D. J.
    Univ Paris Diderot, Lab AIM, IRFU Serv Astrophys, CEA DSM CNRS, Bat 709,CEA Saclay, F-91191 Gif Sur Yvette, France.
    Martino, M.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Marton, G.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Mary, N.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Massari, D.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Matijevic, G.
    AIP, Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany.
    Mazeh, T.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    McMillan, P. J.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Messina, S.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Michalik, D.
    Lund Univ, Dept Astron & Theoret Phys, Lund Observ, Box 43, S-22100 Lund, Sweden.
    Millar, N. R.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Molina, D.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Molinaro, R.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Molnar, L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Montegriffo, P.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Mor, R.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Morbidelli, R.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Morel, T.
    Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Morris, D.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Mulone, A. F.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Muraveva, T.
    Musella, I.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Nelemans, G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Nicastro, L.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Noval, L.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    O'Mullane, W.
    Large Synopt Survey Telescope, 950 N Cherry Ave, Tucson, AZ 85719 USA;ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Ordenovic, C.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Ordonez-Blanco, D.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Osborne, P.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Pagani, C.
    Univ Leicester, Dept Phys & Astron, Leicester Inst Space & Earth Observat, Univ Rd, Leicester LE1 7RH, Leics, England.
    Pagano, I.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Pailler, F.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Palacin, H.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Palaversa, L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Panahi, A.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    Pawlak, M.
    Univ Warsaw Observ, Al Ujazdowskie 4, PL-00478 Warsaw, Poland;Charles Univ Prague, Inst Theoret Phys, Fac Math & Phys, Prague, Czech Republic.
    Piersimoni, A. M.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    Pineau, F. -X
    Plachy, E.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Plum, G.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Poggio, E.
    Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin, Italy;INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Poujoulet, E.
    CNES Ctr Spatial Toulouse, AKKA, 18 Ave Edouard Belin, F-31401 Toulouse 9, France;ESA ESTEC, HE Space Operat BV, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    Prsa, A.
    Villanova Univ, Dept Astrophys & Planetary Sci, 800 Lancaster Ave, Villanova, PA 19085 USA.
    Pulone, L.
    INAF, Osservatorio Astron Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy.
    Racero, E.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Ragaini, S.
    Rambaux, N.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Ramos-Lerate, M.
    ESA ESAC, Vitrociset Belgium, Camino Bajo Castillo S-N, Madrid 28692, Spain;Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA.
    Regibo, S.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Reyle, C.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Riclet, F.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Ripepi, V.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Riva, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Rivard, A.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Rixon, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Roegiers, T.
    ESA ESAC, QUASAR Sci Resources, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Roelens, M.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Romero-Gomez, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Rowell, N.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Royer, F.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Ruiz-Dern, L.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Sadowski, G.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium.
    Sagrista Selles, T.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Sahlmann, J.
    Fork Res, Rua Cruzado Osberno,Lt 1,9 Esq, Lisbon, Portugal;ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Salgado, J.
    CNES Ctr Spatial Toulouse, APAVE SUDEUROPE SAS, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Salguero, E.
    ESA ESAC, ATG Europe, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Sanna, N.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Santana-Ros, T.
    Adam Mickiewicz Univ, Astron Observ Inst, Fac Phys, Sloneczna 36, PL-60286 Poznan, Poland.
    Sarasso, M.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Savietto, H.
    Nord Optic Telescope, Rambla Jose Ana Fernandez Perez 7, Brena Baja 38711, Spain.
    Schultheis, M.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Sciacca, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Segol, M.
    Spanish Virtual Observ, Santander, Spain.
    Segovia, J. C.
    ESA ESAC, Serco Gest Negocios, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Segransan, D.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Shih, I-C
    Siltala, L.
    INAF, Fdn Galileo Galilei, Rambla Jose Ana Fernandez Perez 7, Brena Baja 38712, Santa Cruz Tene, Spain;Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland.
    Silva, A. F.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Smart, R. L.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Smith, K. W.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Solano, E.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N, Madrid 28692, Spain;ESA ESAC, INSA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Solitro, F.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Sordo, R.
    INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Soria Nieto, S.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Souchay, J.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Spagna, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Spoto, F.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France;Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Stampa, U.
    Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Steele, I. A.
    Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England.
    Steidelmueller, H.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Stephenson, C. A.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Stoev, H.
    Univ Complutense Madrid, Dept Arquitectura Computadores & Automat, Fac Informat, C Prof Jose Garcia Santesmases S-N, E-28040 Madrid, Spain.
    Suess, F. F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Surdej, J.
    Univ Liege, Inst Astrophys & Geophys, 19c Allee 6 Aout, B-4000 Liege, Belgium.
    Szabados, L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Szegedi-Elek, E.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Tapiador, D.
    Univ Bristol, HH Wills Phys Lab, Tyndall Ave, Bristol BS8, Avon, England;IEEC, Gran Capita 2-4,08034, Bristol BS8 1TL, Avon, England.
    Taris, F.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Tauran, G.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Taylor, M. B.
    Univ Vigo, Appl Phys Dept, Vigo 36310, Spain.
    Teixeira, R.
    Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226,Cidade Univ, BR-05508900 Sao Paulo, Brazil.
    Terrett, D.
    Rutherford Appleton Lab, STFC, Harwell OX11 0QX, Didcot, England.
    Teyssandier, P.
    Sorbonne Univ, LNE, Univ PSL, Observ Paris,SYRTE,CNRS, 61 Ave Observ, F-75014 Paris, France.
    Thuillot, W.
    Univ Lille, Sorbonne Univ, Univ PSL, Observ Paris,IMCCE, 77 Av Denfert Rochereau, F-75014 Paris, France.
    Titarenko, A.
    Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Bd Observ,CS 34229, F-06304 Nice 4, France.
    Clotet, F. Torra
    Aarhus Univ, Stellar Astrophys Ctr, Dept Phys & Astron, 120 Ny Munkegade,Bldg 1520, DK-8000 Aarhus, Denmark.
    Turon, C.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Ulla, A.
    Univ Bonn, Argelander Inst Astron, Hugel 71, D-53121 Bonn, Germany.
    Utrilla, E.
    ESA ESAC, Aurora Technol, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Uzzi, S.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Vaillant, M.
    CNES Ctr Spatial Toulouse, Thales Serv, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Valentini, G.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    Valette, V.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    van Elteren, A.
    Leiden Univ, Leiden Observ, Niels Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Van Hemelryck, E.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Vaschetto, M.
    ALTEC SpA, Corso Marche 79, I-10146 Turin, Italy.
    Vecchiato, A.
    INAF Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Veljanoski, J.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Viala, Y.
    Univ PSL, GEPI, Observ Paris, CNRS, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Vicente, D.
    Ctr Nacl Super Comp, Barcelona Supercomputing Ctr, C Jordi Girona 29,Ed Nexus 2, Barcelona 08034, Spain.
    Vogt, S.
    ESA ESAC, QUASAR Sci Resources, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    von Essen, C.
    Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Voss, H.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Votruba, V.
    Acad Sci Czech Republ, Astron Inst, Fricova 298, Ondrejov 25165, Czech Republic.
    Voutsinas, S.
    Univ Edinburgh, Royal Observ, Inst Astron, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Walmsley, G.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Weiler, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, Marti I Franques 1, Barcelona 08028, Spain.
    Wertz, O.
    Sorbonne Univ, UPMC Univ, Paris 6 & CNRS, UMR 7095,Inst Astrophys Paris, 98 Bis Bd Arago, F-75014 Paris, France.
    Wevers, T.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Wyrzykowski, L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Warsaw Observ, Al Ujazdowskie 4, PL-00478 Warsaw, Poland.
    Yoldas, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Zerjal, M.
    Tel Aviv Univ, Dept Geosci, IL-6997801 Tel Aviv, Israel;Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia.
    Ziaeepour, H.
    Univ Bourgogne Franche Comte, Inst UTINAM UMR6213, CNRS, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Zorec, J.
    Zschocke, S.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Zucker, S.
    Zurbach, C.
    Univ Montpellier, Lab Univ & Particules Montpellier, Pl Eugene Bataillon,CC72, F-34095 Montpellier 05, France.
    Zwitter, T.
    Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia.
    Observational Hertzsprung-Russell diagrams2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id A10Article in journal (Refereed)
    Abstract [en]

    Context. Gaia Data Release 2 provides high-precision astrometry and three-band photometry for about 1.3 billion sources over the full sky. The precision, accuracy, and homogeneity of both astrometry and photometry are unprecedented. Aims. We highlight the power of the Gaia DR2 in studying many fine structures of the Hertzsprung-Russell diagram (HRD). Gaia allows us to present many different HRDs, depending in particular on stellar population selections. We do not aim here for completeness in terms of types of stars or stellar evolutionary aspects. Instead, we have chosen several illustrative examples. Methods. We describe some of the selections that can be made in Gaia DR2 to highlight the main structures of the Gaia HRDs. We select both field and cluster (open and globular) stars, compare the observations with previous classifications and with stellar evolutionary tracks, and we present variations of the Gaia HRD with age, metallicity, and kinematics. Late stages of stellar evolution such as hot subdwarfs, post-AGB stars, planetary nebulae, and white dwarfs are also analysed, as well as low-mass brown dwarf objects. Results. The Gaia HRDs are unprecedented in both precision and coverage of the various Milky Way stellar populations and stellar evolutionary phases. Many fine structures of the HRDs are presented. The clear split of the white dwarf sequence into hydrogen and helium white dwarfs is presented for the first time in an HRD. The relation between kinematics and the HRD is nicely illustrated. Two different populations in a classical kinematic selection of the halo are unambiguously identified in the HRD. Membership and mean parameters for a selected list of open clusters are provided. They allow drawing very detailed cluster sequences, highlighting fine structures, and providing extremely precise empirical isochrones that will lead to more insight in stellar physics. Conclusions. Gaia DR2 demonstrates the potential of combining precise astrometry and photometry for large samples for studies in stellar evolution and stellar population and opens an entire new area for HRD-based studies.

  • 14.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Excitation and charge transfer in low-energy hydrogen atom collisions with neutral oxygen2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 610, article id A57Article in journal (Refereed)
    Abstract [en]

    Excitation and charge transfer in low-energy O+H collisions is studied; it is a problem of importance for modelling stellar spectra and obtaining accurate oxygen abundances in late-type stars including the Sun. The collisions have been studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals (LCAO) model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multichannel Landau-Zener model. The method has been extended to include configurations involving excited states of hydrogen using an estimate for the two-electron transition coupling, but this extension was found to not lead to any remarkably high rates. Rate coefficients are calculated for temperatures in the range 1000-20000 K, and charge transfer and (de) excitation processes involving the first excited S-states, 4s.S-5(0) and 4s.S-3(0), are found to have the highest rates.

  • 15.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Belyaev, A. K.
    Dickinson, A. S.
    Gadea, F. X.
    Inelastic Na+H collision data for non-LTE applications in stellar atmospheres2010In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 519, p. A20-Article in journal (Refereed)
    Abstract [en]

    Rate coefficients for inelastic Na+H collisions are calculated for all transitions between the ten levels up to and including the ionic state (ion-pair production), namely Na(3s,3p,4s,3d,4p,5s,4d,4f,5p)+H(1s) and Na++H-. The calculations are based on recent full quantum scattering cross-section calculations. The data are needed for non-LTE applications in cool astrophysical environments, especially cool stellar atmospheres, and are presented for a temperature range of 500-8000 K. From consideration of the sensitivity of the cross-sections to input quantum chemical data and the results of different methods for the scattering calculations, a measure of the possible uncertainties in the rate coefficients is estimated.

  • 16.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Belyaev, A. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Guitou, M.
    Feautrier, N.
    Gadea, F. X.
    Spielfiedel, A.
    On inelastic hydrogen atom collisions in stellar atmospheres2011In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 530, p. A94-Article in journal (Refereed)
    Abstract [en]

    The influence of inelastic hydrogen atom collisions on non-LTE spectral line formation has been, and remains to be, a significant source of uncertainty for stellar abundance analyses, due to the difficulty in obtaining accurate data for low-energy atomic collisions either experimentally or theoretically. For lack of a better alternative, the classical "Drawin formula" is often used. Over recent decades, our understanding of these collisions has improved markedly, predominantly through a number of detailed quantum mechanical calculations. In this paper, the Drawin formula is compared with the quantum mechanical calculations both in terms of the underlying physics and the resulting rate coefficients. It is shown that the Drawin formula does not contain the essential physics behind direct excitation by H atom collisions, the important physical mechanism being quantum mechanical in character. Quantitatively, the Drawin formula compares poorly with the results of the available quantum mechanical calculations, usually significantly overestimating the collision rates by amounts that vary markedly between transitions.

  • 17.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Belyaev, A. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Spielfiedel, A.
    Guitou, M.
    Feautrier, N.
    Inelastic Mg plus H collision data for non-LTE applications in stellar atmospheres2012In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 541, p. A80-Article in journal (Refereed)
    Abstract [en]

    Rate coefficients for inelastic Mg+H collisions are calculated for all transitions between the lowest seven levels and the ionic state (charge transfer), namely Mg(3s(2) S-1, 3s3p P-3, 3s3p P-1, 3s4s S-3, 3s4s S-1, 3s3d D-1, 3s4p P-3)+H(1s) and Mg+(3s S-2)+H-. The rate coefficients are based on cross-sections from full quantum scattering calculations, which are themselves based on detailed quantum chemical calculations for the MgH molecule. The data are needed for non-LTE applications in cool astrophysical environments, especially cool stellar atmospheres, and are presented for a temperature range of 500-8000 K. From consideration of the sensitivity of the cross-sections to various uncertainties in the calculations, most importantly input quantum chemical data and the numerical accuracy of the scattering calculations, a measure of the possible uncertainties in the rate coefficients is estimated.

  • 18.
    Barklem, Paul
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Osorio, Y.
    Instituto de Astrofísica de Canarias, vía Láctea.; Universidad de La Laguna, Departamento de Astrofísica.; Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg.
    Fursa, D. V.
    Curtin Institute for Computation, Kent Street.; Department of Physics, Astronomy and Medical Radiation Science, Kent Street.
    Bray, I.
    Curtin Institute for Computation, Kent Street.; Department of Physics, Astronomy and Medical Radiation Science, Kent Street.
    Zatsarinny, O.
    Drake University, Department of Physics and Astronomy.
    Bartschat, K.
    Drake University, Department of Physics and Astronomy.
    Jerkstrand, A.
    Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching.
    Inelastic e plus Mg collision data and its impact on modelling stellar and supernova spectra2017In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 606, article id A11Article in journal (Refereed)
    Abstract [en]

    Results of calculations for inelastic e+Mg effective collision strengths for the lowest 25 physical states of Mg I (up to 3s6p P-1), and thus 300 transitions, from the convergent close-coupling (CCC) and the B-spline R-matrix (BSR) methods are presented. At temperatures of interest, similar to 5000 K, the results of the two calculations differ on average by only 4%,with a scatter of 27%. As the methods are independent, this suggests that the calculations provide datasets for e+Mg collisions accurate to this level. Comparison with the commonly used dataset compiled by Mauas et al. (1988, ApJ, 330, 1008), covering 25 transitions among 12 states, suggests the Mauas et al. data are on average similar to 57% too low, and with a very large scatter of a factor of similar to 6.5. In particular the collision strength for the transition corresponding to the Mg I intercombination line at 457 nm is significantly underestimated by Mauas et al., which has consequences for models that employ this dataset. In giant stars the new data leads to a stronger line compared to previous non-LTE calculations, and thus a reduction in the non-LTE abundance correction by similar to 0.1 dex (similar to 25%). A non-LTE calculation in a supernova ejecta model shows this line becomes significantly stronger, by a factor of around two, alleviating the discrepancy where the 457 nm line in typical models with Mg/O ratios close to solar tended to be too weak compared to observations.

  • 19.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Accurate abundance analysis of late-type stars: advances in atomic physics2016In: The Astronomy and Astrophysics Review, ISSN 0935-4956, E-ISSN 1432-0754, Vol. 24, article id 9Article, review/survey (Refereed)
    Abstract [en]

    The measurement of stellar properties such as chemical compositions, masses and ages, through stellar spectra, is a fundamental problem in astrophysics. Progress in the understanding, calculation and measurement of atomic properties and processes relevant to the high-accuracy analysis of F-, G-, and K-type stellar spectra is reviewed, with particular emphasis on abundance analysis. This includes fundamental atomic data such as energy levels, wavelengths, and transition probabilities, as well as processes of photoionisation, collisional broadening and inelastic collisions. A recurring theme throughout the review is the interplay between theoretical atomic physics, laboratory measurements, and astrophysical modelling, all of which contribute to our understanding of atoms and atomic processes, as well as to modelling stellar spectra.

  • 20.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Excitation and charge transfer in low-energy hydrogen atom collisions with neutral iron2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 612, article id A90Article in journal (Refereed)
    Abstract [en]

    Data for inelastic processes due to hydrogen atom collisions with iron are needed for accurate modelling of the iron spectrum in late-type stars. Excitation and charge transfer in low-energy Fe+H collisions is studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multi-channel Landau-Zener model. An extensive calculation including 166 covalent states and 25 ionic states is presented and rate coefficients are calculated for temperatures in the range 1000-20 000 K. The largest rates are found for charge transfer processes to and from two clusters of states around 6.3 and 6.6 eV excitation, corresponding in both cases to active 4d and 5p electrons undergoing transfer. Excitation and de-excitation processes among these two sets of states are also significant.

  • 21.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Hydrogen Atom Collision Processes in Cool Stellar Atmospheres: Effects on Spectral Line Strengths and Measured Chemical Abundances in Old Stars2012In: XXI INTERNATIONAL CONFERENCE ON SPECTRAL LINE SHAPES (ICSLS 2012), 2012, p. 012049-Conference paper (Refereed)
    Abstract [en]

    The precise measurement of the chemical composition of stars is a fundamental problem relevant to many areas of astrophysics. State-of-the-art approaches attempt to unite accurate descriptions of microphysics, non-local thermodynamic equilibrium (non-LTE) line formation and 3D hydrodynamical model atmospheres. In this paper I review progress in understanding inelastic collisions of hydrogen atoms with other species and their influence on spectral line formation and derived abundances in stellar atmospheres. These collisions are a major source of uncertainty in non-LTE modelling of spectral lines and abundance determinations, especially for old, metal-poor stars, which are unique tracers of the early evolution of our galaxy. Full quantum scattering calculations of direct excitation processes X(nl) + H <-> X(n'l') + H and charge transfer processes X(nl) + H <-> X+ + H- have been done for Li, Na and Mg [1,2,3] based on detailed quantum chemical data, e.g. [4]. Rate coefficients have been calculated and applied to non-LTE modelling of spectral lines in stellar atmospheres [5,6,7,8,9]. In all cases we find that charge transfer processes from the first excited S-state are very important, and the processes affect measured abundances for Li, Na and Mg in some stars by as much as 60%. Effects vary with stellar parameters (e.g. temperature, luminosity, metal content) and so these processes are important not only for accurate absolute abundances, but also for relative abundances among dissimilar stars.

  • 22.
    Barklem, Paul S.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Osorio, Yeisson Fabian Martinez
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Modelling the spectrum of Mg in cool stars2014In: XXII International Conference on Spectral Line Shapes (ICSLS 2014), 2014, p. 012001-, article id 012001Conference paper (Refereed)
    Abstract [en]

    The astrophysical importance of Mg, together with its unique range of spectral features in late-type stars, plus its relative simplicity from an atomic physics point of view, makes it a prime target and test bed for detailed ab initio non-local thermodynamic equilibrium (NLTE) modelling in stellar atmospheres. In this paper, we present example first results for calculations of NLTE Mg line based on a new model atom with significant improvements in the collision data for neutral Mg. We perform calculations for excitation of the lower-lying levels due to electron impacts using the R-matrix method. Recent data for excitation and charge transfer due to hydrogen atom impacts involving low-lying levels are now employed. Further, we have made efforts to use physically-motivated methods for calculating radiative and collisional data involving Rydberg states. The results are compared with observed spectra and the impact of the new calculations briefly explored.

  • 23.
    Barucci, M. A.
    et al.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Filacchione, G.
    INAF IAPS, I-00133 Rome, Italy..
    Fornasier, S.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France.;Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Raponi, A.
    INAF IAPS, I-00133 Rome, Italy..
    Deshapriya, J. D. P.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Tosi, F.
    INAF IAPS, I-00133 Rome, Italy..
    Feller, C.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France.;Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Ciarniello, M.
    INAF IAPS, I-00133 Rome, Italy..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Capaccioni, F.
    INAF IAPS, I-00133 Rome, Italy..
    Pommerol, A.
    Univ Bern, Inst Phys, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Massironi, M.
    Univ Padua, Dipartimento Geosci, I-35122 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Merlin, F.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France.;Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Vincent, J. -B
    Fulchignoni, M.
    Univ Paris Diderot, Sorbonne Paris Cite, 4 Rue Elsa Morante, F-75205 Paris 13, France..
    Guilbert-Lepoutre, A.
    Observ Sci Univers, F-25000 Besancon, France..
    Perna, D.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Capria, M. T.
    INAF IAPS, I-00133 Rome, Italy..
    Hasselmann, P. H.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Rousseau, B.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, Vic Osservatorio 3, I-35122 Padua, Italy..
    Bockelee-Morvan, D.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Lamy, P. L.
    Aix Marseille Univ, F-13388 Marseille 13, France..
    De Sanctis, C.
    INAF IAPS, I-00133 Rome, Italy..
    Rodrigo, R.
    CSIC INTA, Ctr Astrobiol, Madrid 28850, Spain.;Univ Bern, Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Erard, S.
    Koschny, D.
    European Space Agcy, Res & Sci Support Dept, NL-2201 Noordwijk, Netherlands..
    Leyrat, C.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. PAS Space Res Ctr, Bartycka 18A, PL-00716 Warsaw, Poland..
    Drossart, P.
    UPMC Univ Paris 06, Univ Paris Diderot, CNRS, Observ Paris,LESIA, 5 Pl J Janssen, F-92195 Meudon, France..
    Keller, H. U.
    TU Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Arnold, G.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Bertaux, J. -L
    Bertini, I.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Cerroni, P.
    INAF IAPS, I-00133 Rome, Italy..
    Cremonese, G.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Da Deppo, V.
    Univ Padua, Dept Informat Engn, Via Gradenigo 6, I-35131 Padua, Italy..
    Davidsson, B. J. R.
    JPL, 4800 Oak Grove Dr, Pasadena, CA 91109 USA..
    El-Maarry, M. R.
    Univ Bern, Inst Phys, Sidlerstr 5, CH-3012 Bern, Switzerland..
    Fonti, S.
    Univ Salento, Dipartimento Fis, Lecce, LE, Italy..
    Fulle, M.
    Osserv Astron Trieste, INAF, Via Tiepolo 11, I-34143 Trieste, Italy..
    Groussin, O.
    CNRS, Lab Astrophys Marseille, UMR 7326, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hviid, S. F.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Ip, W.
    Natl Cent Univ, Inst Space Sci, Chungli 32054, Taiwan..
    Jorda, L.
    CNRS, Lab Astrophys Marseille, UMR 7326, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Kappel, D.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Knollenberg, J.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kramm, J. -R
    Kuehrt, E.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kuppers, M.
    ESA ESAC, POB 78, Villanueva De La Canada 28691, Spain..
    Lara, L.
    CSIC, Inst Astrofis Andalucia, Granada 18080, Spain..
    Lazzarin, M.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Moreno, J. J. Lopez
    CSIC, Inst Astrofis Andalucia, Granada 18080, Spain..
    Mancarella, F.
    Univ Salento, Dipartimento Fis, Lecce, LE, Italy..
    Marzari, F.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Mottola, S.
    DLR, Inst Planetary Res, Rutherfordstr 2, D-12489 Berlin, Germany..
    Naletto, G.
    Univ Padua, Dept Informat Engn, Via Gradenigo 6, I-35131 Padua, Italy..
    Pajola, M.
    NASA, Ames Res Ctr, Moffett Field, CA 94035 USA..
    Palomba, E.
    INAF IAPS, I-00133 Rome, Italy..
    Quirico, E.
    UJF Grenoble 1, CNRS INSU, F-38400 St Martin Dheres, France..
    Schmitt, B.
    UJF Grenoble 1, CNRS INSU, F-38400 St Martin Dheres, France..
    Thomas, N.
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Detection of exposed H2O ice on the nucleus of comet 67P/Churyumov-Gerasimenko as observed by Rosetta OSIRIS and VIRTIS instruments2016In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 595, article id A102Article in journal (Refereed)
    Abstract [en]

    Context. Since the orbital insertion of the Rosetta spacecraft, comet 67P/Churyumov-Gerasimenko (67P) has been mapped by OSIRIS camera and VIRTIS spectro-imager, producing a huge quantity of images and spectra of the comet's nucleus. Aims. The aim of this work is to search for the presence of H2O on the nucleus which, in general, appears very dark and rich in dehydrated organic material. After selecting images of the bright spots which could be good candidates to search for H2O ice, taken at high resolution by OSIRIS, we check for spectral cubes of the selected coordinates to identify these spots observed by VIRTIS. Methods. The selected OSIRIS images were processed with the OSIRIS standard pipeline and corrected for the illumination conditions for each pixel using the Lommel-Seeliger disk law. The spots with higher I/F were selected and then analysed spectrophotometrically and compared with the surrounding area. We selected 13 spots as good targets to be analysed by VIRTIS to search for the 2 mu m absorption band of water ice in the VIRTIS spectral cubes. Results. Out of the 13 selected bright spots, eight of them present positive H2O ice detection on the VIRTIS data. A spectral analysis was performed and the approximate temperature of each spot was computed. The H2O ice content was confirmed by modeling the spectra with mixing (areal and intimate) of H2O ice and dark terrain, using Hapke's radiative transfer modeling. We also present a detailed analysis of the detected spots.

  • 24.
    Battino, U.
    et al.
    Univ Basel, Dept Phys, Klingelbergstr 82, CH-4056 Basel, Switzerland..
    Pignatari, M.
    Univ Hull, Dept Math & Phys, EA Milne Ctr Astrophys, Kingston Upon Hull HU6 7RX, N Humberside, England.;Hungarian Acad Sci, Res Ctr Astron & Earth Sci, Konkoly Observ, Konkoly Thege Mikls T 15-17, H-1121 Budapest, Hungary..
    Ritter, C.
    Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 5C2, Canada.;JINA Ctr Evolut Elements, E Lansing, MI USA..
    Herwig, F.
    Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 5C2, Canada.;JINA Ctr Evolut Elements, E Lansing, MI USA..
    Denisenkov, P.
    Univ Victoria, Dept Phys & Astron, Victoria, BC V8P 5C2, Canada.;JINA Ctr Evolut Elements, E Lansing, MI USA.;TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada..
    Den Hartogh, J. W.
    Keele Univ, Keele ST5 5BG, Staffs, England..
    Trappitsch, R.
    Dept Geophys Sci, Chicago, IL 60637 USA.;Chicago Ctr Cosmochem, Chicago, IL 60637 USA..
    Hirschi, R.
    Keele Univ, Keele ST5 5BG, Staffs, England.;Univ Tokyo, Inst Phys & Math Universe WPI, 5-1-5 Kashiwanoha, Kashiwa, Chiba 2778583, Japan..
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Thielemann, F.
    Univ Basel, Dept Phys, Klingelbergstr 82, CH-4056 Basel, Switzerland..
    Paxton, B.
    Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Kohn Hall, Santa Barbara, CA 93106 USA.;Univ Calif Santa Barbara, Dept Phys, Kohn Hall, Santa Barbara, CA 93106 USA..
    Application Of A Theory And Simulation-Based Convective Boundary Mixing Model For AGB Star Evolution And Nucleosynthesis2016In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 827, no 1, article id 30Article in journal (Refereed)
    Abstract [en]

    The s-process nucleosynthesis in Asymptotic giant branch (AGB) stars depends on the modeling of convective boundaries. We present models and s-process simulations that adopt a treatment of convective boundaries based on the results of hydrodynamic simulations and on the theory of mixing due to gravity waves in the vicinity of convective boundaries. Hydrodynamics simulations suggest the presence of convective boundary mixing (CBM) at the bottom of the thermal pulse-driven convective zone. Similarly, convection-induced mixing processes are proposed for the mixing below the convective envelope during third dredge-up (TDU), where the C-13 pocket for the s process in AGB stars forms. In this work, we apply a CBM model motivated by simulations and theory to models with initial mass M = 2 andM = 3M(circle dot), and with initial metal content Z = 0.01 and Z = 0.02. As reported previously, the He-intershell abundances of C-12 and O-16 are increased by CBM at the bottom of the pulse-driven convection zone. This mixing is affecting the Ne-22(alpha, n)Mg-25 activation and the s-process efficiency in the C-13-pocket. In our model, CBM at the bottom of the convective envelope during the TDU represents gravity wave mixing. Furthermore, we take into account the fact that hydrodynamic simulations indicate a declining mixing efficiency that is already about a pressure scale height from the convective boundaries, compared to mixing-length theory. We obtain the formation of the C-13-pocket with a mass of approximate to 10(-4) M-circle dot. The final s-process abundances are characterized by 0.36<[s/Fe] < 0.78 and the heavy-to-light s-process ratio is -0.23< [hs/ls] < 0.45. Finally, we compare our results with stellar observations, presolar grain measurements and previous work.

  • 25.
    Belyaev, A. K.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Paradoxes of the standard adiabatic born-oppenheimer approach to collision processes: Their origin and possible solutions2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 9, p. 092005-Article in journal (Refereed)
    Abstract [en]

    It is demonstrated that conventional applications of the standard adiabatic Born-Oppenheimer approach lead to paradoxes such as nonzero inelastic cross sections for noninteracting collision systems and infinite inelastic collision cross sections. The origin of these paradoxes is the molecular state problem. The quantum solution of the problem, the multielectron reprojection method, is proposed within the standard BO approach.

  • 26. Belyaev, A. K.
    et al.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Dickinson, A. S.
    Gadea, F. X.
    Cross sections for low-energy inelastic H plus Na collisions2010In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 81, no 3, p. 032706-Article in journal (Refereed)
    Abstract [en]

    Full quantum-scattering calculations are reported for low-energy near-threshold inelastic collision cross sections for H + Na. The calculations include transitions between all levels up to and including the ionic state (ion-pair production) for collision energies from the threshold up to 10 eV. These results are important for astrophysical modeling of spectra in stellar atmospheres. Results for the 3s-3p excitation are carefully examined using three different quantum chemistry input data sets, and large differences are found near the threshold. The differences are found to be predominantly due to differences in the radial coupling rather than potentials and are also found not to relate to differences in couplings in a simple manner. In fact, of the three input couplings, the two that are most similar give the cross sections with the largest differences. The 3s-3p cross sections show orbiting resonances which have been seen in earlier studies, while Feshbach resonances associated with closed channels were also found to be present in the low-energy cross sections for some transitions.

  • 27.
    Belyaev, Andrey K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Gadéa, F. X.
    Vlasov, D. V.
    Low-energy inelastic Na + H collisions2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 9, p. 092001-Article in journal (Refereed)
    Abstract [en]

    We report full quantum scattering calculations for near-threshold collision cross sections for excitation of Na by H. The calculations include contributions from transitions between all singlet states up to and including the ionic state (ion-pair production). The dynamics calculations are based on three sets of recent ab initio and pseudo-potential quantum-chemical calculations. Considerable sensitivity to the couplings employed is found.

  • 28.
    Belyaev, Andrey K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Guitou, M.
    Spielfiedel, A.
    Feautrier, N.
    Vlasov, D. V.
    Rodionov, D. S.
    Ab initio cross sections for low-energy inelastic Mg+H collisions2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 9, p. 092002-Article in journal (Refereed)
    Abstract [en]

    Full quantum scattering calculations of cross sections for low-energy near-threshold inelastic Mg + H collisions are reported, such processes being of interest for modelling of Mg spectral lines in stellar atmospheres. Nonadiabatic transions associated with radial couplings at avoided ionic crossings in the 2Σ+ molecular states are found to be the main mechanism for excitation and ion-pair production processes.

  • 29.
    Belyaev, Andrey K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Spielfiedel, A.
    Guitou, M.
    Feautrier, N.
    Rodionov, D. S.
    Vlasov, D. V.
    Cross sections for low-energy inelastic Mg + H and Mg+ + H- collisions2012In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 85, no 3, p. 032704-Article in journal (Refereed)
    Abstract [en]

    We report full quantum scattering calculations for low-energy near-threshold inelastic cross sections in Mg + H and Mg+ + H- collisions. The calculations include all transitions between the eight lowest adiabatic MgH((2)Sigma(+)) molecular states, with the uppermost of those diabatically extended to the ionic molecular state in the asymptotic region. This allows us to treat the excitation processes between the seven lowest atomic states of magnesium in collisions with hydrogen atoms, as well as the ion-pair production and the mutual neutralization processes. The collision energy range is from threshold up to 10 eV. These results are important for astrophysical modeling of spectra in stellar atmospheres. The processes in question are carefully examined and several process mechanisms are found. Some mechanisms are determined by interactions between ionic and covalent configurations at relatively large internuclear distances, while others are based on short-range nonadiabatic regions due to interactions between covalent configurations.

  • 30.
    Belyaev, Andrey K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Lebedev, O. V.
    Domcke, W.
    Nonadiabatic nuclear dynamics in the ammonia cation studied by the branching classical trajectory method2012In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 388, no 10, p. 102005-Article in journal (Refereed)
    Abstract [en]

    The photoinduced nonadiabatic nuclear dynamics of the ammonia cation is studied by the branching classical trajectory approach. The time-dependent populations of different electronic states of the ammonia cation are calculated and are in good agreement with the results of full quantum calculations.

  • 31.
    Belyaev, Andrey K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Lebedev, Oleg V.
    Nonadiabatic nuclear dynamics of atomic collisions based on branching classical trajectories2011In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 84, no 1, p. 014701-Article in journal (Refereed)
    Abstract [en]

    The branching classical trajectory method for inelastic atomic collision processes is proposed. The approach is based on two features: (i) branching of a classical trajectory in a nonadiabatic region and (ii) the nonadiabatic transition probability formulas particularly adapted for a classical trajectory treatment. In addition to transition probabilities and inelastic cross sections, the proposed approach allows one to calculate incoming and outgoing currents. The method is applied to inelastic Na + H collisions providing the results in reasonable agreement with full quantum calculations.

  • 32.
    Belyaev, Andrey K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Yakovleva, Svetlana A.
    Barklem, Paul S.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Inelastic silicon-hydrogen collision data for non-LTE applications in stellar atmospheres2014In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 572, p. A103-Article in journal (Refereed)
    Abstract [en]

    Aims. Inelastic processes in low-energy Si + H and Si+ + H- collisions are treated for the states from the ground state up to the ionic state, in order to provide rate coefficients needed for non-LTE modeling of Si in cool stellar atmospheres. Methods. Electronic molecular structure is determined using a recently proposed model approach based on an asymptotic method in combination with available ab initio potentials. Nonadiabatic nuclear dynamics are treated by means of a combination of multichannel formulas and the branching-probability-current method, based on the Landau-Zener model for nonadiabatic transition probabilities. Results. Cross sections and rate coefficients for inelastic processes in Si + H and Si+ + H- collisions for all transitions between 26 low-lying states plus the ionic state are calculated. It is shown that the highest rate coefficient values correspond to the excitation, de-excitation, ion-pair formation, and mutual neutralization processes involving the Si(3p4p D-3), Si(3p3d F-3), Si(3p4p D-1), Si(3p3d P-3), Si(3p4p S-1), and the ionic Si+ + H- states. These processes are likely to be important in non-LTE modeling.

  • 33. Bergemann, M.
    et al.
    Ruchti, G. R.
    Serenelli, A.
    Feltzing, S.
    Alves-Brito, A.
    Asplund, M.
    Bensby, T.
    Gruyters, Pieter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Hourihane, A.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Lind, K.
    Marino, A.
    Jofre, P.
    Nordlander, T.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Ryde, N.
    Worley, C. C.
    Gilmore, G.
    Randich, S.
    Ferguson, A. M. N.
    Jeffries, R. D.
    Micela, G.
    Negueruela, I.
    Prusti, T.
    Rix, H. -W
    Vallenari, A.
    Alfaro, E. J.
    Allende Prieto, C.
    Bragaglia, A.
    Koposov, S. E.
    Lanzafame, A. C.
    Pancino, E.
    Recio-Blanco, A.
    Smiljanic, R.
    Walton, N.
    Costado, M. T.
    Franciosini, E.
    Hill, V.
    Lardo, C.
    de Laverny, P.
    Magrini, L.
    Maiorca, E.
    Masseron, T.
    Morbidelli, L.
    Sacco, G.
    Kordopatis, G.
    Tautvaisiene, G.
    The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk2014In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 565, p. A89-Article in journal (Refereed)
    Abstract [en]

    We study the relationship between age, metallicity, and alpha-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the observed dataset, i.e. the accuracy of stellar parameters and the selection effects that are caused by the photometric target preselection. We find that the colour and magnitude cuts in the survey suppress old metal-rich stars and young metal-poor stars. This suppression may be as high as 97% in some regions of the age-metallicity relationship. The dataset consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr, Galactocentric distances from 6 kpc to 9.5 kpc, and vertical distances from the plane 0 < vertical bar Z vertical bar < 1.5 kpc. On this basis, we find that i) the observed age-metallicity relation is nearly flat in the range of ages between 0 Gyr and 8 Gyr; ii) at ages older than 9 Gyr, we see a decrease in [Fe/H] and a clear absence of metal-rich stars; this cannot be explained by the survey selection functions; iii) there is a significant scatter of [Fe/H] at any age; and iv) [Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages > 9 Gyr is not as small as advocated by some other studies. In agreement with earlier work, we find that radial abundance gradients change as a function of vertical distance from the plane. The [Mg/Fe] gradient steepens and becomes negative. In addition, we show that the inner disk is not only more alpha-rich compared to the outer disk, but also older, as traced independently by the ages and Mg abundances of stars.

  • 34.
    Bertini, I.
    et al.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Marzari, F.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Moreno, F.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Pajola, M.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy..
    La Forgia, F.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Lamy, P.
    CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille 13, France.;Aix Marseille Univ, F-13388 Marseille 13, France..
    Rodrigo, R.
    CSIC INTA, Ctr Astrobiol, Madrid 28850, Spain.;Int Space Sci Inst, CH-3012 Bern, Switzerland..
    Koschny, D.
    European Space Agcy, Res & Sci Support Dept, NL-2201 Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Keller, H. U.
    Tech Univ Carolo Wilhelmina Braunschweig, Inst Geophys & Extraterr Phys, D-38106 Braunschweig, Germany..
    Agarwal, J.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Barucci, M. A.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Observ Paris, F-92195 Meudon Pricipal, France..
    Bertaux, J. -L
    Cremonese, G.
    INAF Osservatorio Astron Padova, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy..
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Debei, S.
    Univ Padua, Dept Ind Engn, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trent, UNITN, I-38100 Trento, Italy..
    Ferri, F.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy..
    Fornasier, S.
    Univ Paris Diderot, Univ Paris 06, CNRS, LESIA,Observ Paris, F-92195 Meudon Pricipal, France.;Univ Paris Diderot, Sorbonne Paris Cite, F-75205 Paris 13, France..
    Fulle, M.
    INAF Osservatorio Astron Trieste, I-34143 Trieste, Italy..
    Giacomini, L.
    Univ Padua, Dept Geosci, I-35131 Padua, Italy..
    Groussin, O.
    Aix Marseille Univ, CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille, France..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Hviid, S. F.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Ip, W. -H
    Jorda, L.
    Aix Marseille Univ, CNRS, UMR 7326, Lab Astrophys Marseille, F-13388 Marseille, France..
    Knollenberg, J.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kramm, J. R.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Kuehrt, E.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Kueppers, M.
    ESA ESAC, Villanueva De La Canada 28691, Spain..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Lopez Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain..
    Magrin, S.
    Univ Padua, Dept Phys & Astron G Galilei, I-35122 Padua, Italy..
    Massironi, M.
    Univ Padua, Dept Geosci, I-35131 Padua, Italy..
    Michalik, H.
    Inst Datentech & Kommunikat Netze, D-38106 Braunschweig, Germany..
    Mottola, S.
    DLR, Inst Planetary Res, D-12489 Berlin, Germany..
    Naletto, G.
    Univ Padua, Ctr Studies & Act Space CISAS G Colombo, I-35131 Padua, Italy.;CNR IFN UOS Padova LUXOR, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Thomas, N.
    Univ Bern, Inst Phys, CH-3012 Bern, Switzerland..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, D-37077 Gottingen, Germany..
    Vincent, J. -B
    Search for satellites near comet 67P/Churyumov-Gerasimenko using Rosetta/OSIRIS images2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 583, article id A19Article in journal (Refereed)
    Abstract [en]

    Context. The European Space Agency Rosetta mission reached and started escorting its main target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, at the beginning of August 2014. Within the context of solar system small bodies, satellite searches from approaching spacecraft were extensively used in the past to study the nature of the visited bodies and their collisional environment. Aims. During the approaching phase to the comet in July 2014, the OSIRIS instrument onboard Rosetta performed a campaign aimed at detecting objects in the vicinity of the comet nucleus and at measuring these objects' possible bound orbits. In addition to the scientific purpose, the search also focused on spacecraft security to avoid hazardous material in the comet's environment. Methods. Images in the red spectral domain were acquired with the OSIRIS Narrow Angle Camera, when the spacecraft was at a distance between 5785 km and 5463 km to the comet, following an observational strategy tailored to maximize the scientific outcome. From the acquired images, sources were extracted and displayed to search for plausible displacements of all sources from image to image. After stars were identified, the remaining sources were thoroughly analyzed. To place constraints on the expected displacements of a potential satellite, we performed Monte Carlo simulations on the apparent motion of potential satellites within the Hill sphere. Results. We found no unambiguous detections of objects larger than similar to 6 m within similar to 20 km and larger than similar to 1 m between similar to 20 km and similar to 110 km from the nucleus, using images with an exposure time of 0.14 s and 1.36 s, respectively. Our conclusions are consistent with independent works on dust grains in the comet coma and on boulders counting on the nucleus surface. Moreover, our analysis shows that the comet outburst detected at the end of April 2014 was not strong enough to eject large objects and to place them into a stable orbit around the nucleus. Our findings underline that it is highly unlikely that large objects survive for a long time around cometary nuclei.

  • 35. Bertini, Ivano
    et al.
    Sabolo, Walter
    Gutierrez, Pedro J.
    Marzari, Francesco
    Snodgrass, Colin
    Tubiana, Cecilia
    Moissl, Richard
    Pajola, Maurizio
    Lowry, Stephen C.
    Barbieri, Cesare
    Ferri, Francesca
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Sierks, Holger
    Search for satellites near (21) Lutetia using OSIRIS/Rosetta images2012In: Planetary and Space Science, ISSN 0032-0633, E-ISSN 1873-5088, Vol. 66, no 1, p. 64-70Article in journal (Refereed)
    Abstract [en]

    On 2010 July 10 the ESA Rosetta mission flew by the large asteroid (21) Lutetia. One of the scientific goals of the onboard OSIRIS instrument was the search for satellites of the asteroid, with more than 20 images specifically dedicated to this topic. An observational campaign was devised with a selection of filters and exposure times tailored to maximize the possibility of detecting small companions and determining their bound orbits. Data were analyzed with suitable methods to remove cosmic ray hits and known background objects, in order to search for persistent detections of potential interesting flux sources. We found no unambiguous detections of a satellite larger than similar to 160 m inside the entire sphere of gravitational influence. Our search confirmed the absence of bound companions larger than similar to 30 m inside 20 primary radii. These limits are a factor of similar to 30 smaller than the values reported so far from large ground-based telescopes using adaptive optics and from the Hubble Space Telescope.

  • 36.
    Bladh, S.
    et al.
    Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Paladini, C.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium..
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Aringer, B.
    Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Tomography of silicate dust around M-type AGB stars I. Diagnostics based on dynamical models2017In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 607, article id A27Article in journal (Refereed)
    Abstract [en]

    Context: The heavy mass loss observed in evolved asymptotic giant branch stars is usually attributed to a two-step process: atmospheric levitation by pulsation-induced shock waves, followed by radiative acceleration of newly formed dust grains. Detailed wind models suggest that the outflows of M-type AGB stars may be triggered by photon scattering on Fe-free silicates with grain sizes of about 0.1-1 mu m. As a consequence of the low grain temperature, these Fe-free silicates can condense close to the star, but they do not produce the characteristic mid-IR features that are often observed in M-type AGB stars. However, it is probable that the silicate grains are gradually enriched with Fe as they move away from the star, to a degree where the grain temperature stays below the sublimation temperature, but is high enough to produce emission features.

    Aims: We investigate whether differences in grain temperature in the inner wind region, which are related to changes in the grain composition, can be detected with current interferometric techniques, in order to put constraints on the wind mechanism.

    Methods: We use phase-dependent radial structures of the atmosphere and wind of an M-type AGB star, produced with the 1D radiation-hydrodynamical code DARWIN, to investigate if current interferometric techniques can differentiate between the temperature structures that give rise to the same overall spectral energy distribution.

    Results: The spectral energy distribution is found to be a poor indicator of different temperature profiles and therefore is not a good tool for distinguishing different scenarios of changing grain composition. However, spatially resolved interferometric observations have promising potential. They show signatures even for Fe-free silicates (found at 2-3 stellar radii), in contrast to the spectral energy distribution. Observations with baselines that probe spatial scales of about 4 stellar radii and beyond are suitable for tracing changes in grain composition, since this is where effects of Fe enrichment should be found.

  • 37.
    Bladh, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Exploring wind-driving dust species in cool luminous giants: I. Basic criteria and dynamical models of M-type AGB stars2012In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 546, p. A76-Article in journal (Refereed)
    Abstract [en]

    Context. The heavy mass loss observed in evolved asymptotic giant branch stars is usually attributed to a two-stage process: atmospheric levitation by pulsation-induced shock waves followed by radiative acceleration of dust grains, which transfer momentum to the surrounding gas through collisions. In order for an outflow to occur the two stages of the mass-loss scheme have to connect, i.e., the radiative acceleration can only be initiated if the levitated gas reaches a distance from the stellar photosphere where dust particles can condense. This levitation distance is limited by the kinetic energy transferred to the gas by the shock waves, which imposes strict constraints on potential wind-driving dust species. Aims. This work is part of an ongoing effort aiming at identifying the actual wind-drivers among the dust species observed in circumstellar envelopes. In particular, we focus on the interplay between a strong stellar radiation field and the dust formation process. Methods. To identify critical properties of potential wind-driving dust species we use detailed radiation-hydrodynamical models which include a parameterized dust description, complemented by simple analytical estimates to help with the physical interpretation of the numerical results. The adopted dust description is constructed to mimic different chemical and optical dust properties in order to systematically study the effects of a realistic radiation field on the second stage of the mass loss mechanism. Results. We see distinct trends in which combinations of optical and chemical dust properties are needed to trigger an outflow. Dust species with a low condensation temperature and a near-infrared absorption coefficient that decreases strongly with wavelength will not condense close enough to the stellar surface to be considered as potential wind-drivers. Conclusions. Our models confirm that metallic iron and Fe-bearing silicates are not viable as wind-drivers due to their near-infrared optical properties and resulting large condensation distances. TiO2 is also excluded as a wind-driver due to the low abundance of Ti. Other species, such a SiO2 and Al2O3, are less clear-cut cases due to uncertainties in the optical and chemical data and further work is needed. A strong candidate is Mg2SiO4 with grain sizes of 0.1-1 mu m, where scattering contributes significantly to the radiative acceleration, as suggested by earlier theoretical work and supported by recent observations.

  • 38.
    Bladh, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Aringer, B.
    Dust in AGB Stars: Transparent or Opaque?2011In: Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants, 2011, Vol. 445Conference paper (Refereed)
    Abstract [en]

    The optical properties of the dust particles that drive the winds of cool giant stars affect the stellar spectra in two ways: (1) indirectly, through their influence on the dynamical structure of the atmosphere/envelope and the resulting molecular features, and (2) directly, by changes of the spectral energy distribution due to absorption and scattering on dust grains. The qualitative differences in the energy distributions of C-type and M-type AGB stars in the visual and near-infrared regions suggest that the dust particles in oxygen rich atmospheres are relatively transparent to radiation. By using detailed dynamical models of gas and radiation combined with a simple description for the dust opacity (which can be adjusted to mimic different wavelength dependences and condensation temperatures) and also by adjusting the fraction of the opacity that is treated as true absorption, we investigate which dust properties produce synthetic photometry consistent with observations. The goal of this study is to narrow down the possible dust species that may be driving the winds in M-type AGB stars.

  • 39.
    Bladh, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Höfner, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Nowotny, W.
    Aringer, B.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Exploring wind-driving dust species in cool luminous giants II. Constraints from photometry of M-type AGB stars2013In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 553, p. A20-Article in journal (Refereed)
    Abstract [en]

    Context. The heavy mass loss observed in evolved asymptotic giant branch (AGB) stars is usually attributed to a two-stage process: atmospheric levitation by pulsation-induced shock waves, followed by radiative acceleration of newly formed dust grains. The dust transfers momentum to the surrounding gas through collisions and thereby triggers a general outflow. Radiation-hydrodynamical models of M-type AGB stars suggest that these winds can be driven by photon scattering - in contrast to absorption - on Fe-free silicate grains of sizes 0.1-1 mu m. Aims. In this paper we study photometric constraints for wind-driving dust species in M-type AGB stars, as part of an ongoing effort to identify likely candidates among the grain materials observed in circumstellar envelopes. Methods. To investigate the scenario of stellar winds driven by photon scattering on dust, and to explore how different optical and chemical properties of wind-driving dust species affect photometry we focus on two sets of dynamical models atmospheres: (i) models using a detailed description for the growth of Mg2SiO4 grains, taking into account both scattering and absorption cross-sections when calculating the radiative acceleration; and (ii) models using a parameterized dust description, constructed to represent different chemical and optical dust properties. By comparing synthetic photometry from these two sets of models to observations of M-type AGB stars we can provide constraints on the properties of wind-driving dust species. Results. Photometry from wind models with a detailed description for the growth of Mg2SiO4 grains reproduces well both the values and the time-dependent behavior of observations of M-type AGB stars, providing further support for the scenario of winds driven by photon scattering on dust. The photometry from the models with a parameterized dust description suggests that wind-drivers need to have a low absorption cross-section in the visual and near-IR to reproduce the time-dependent behavior, i. e. small variations in (J-K) and spanning a larger range in (V-K). This places constraints on the optical and chemical properties of the wind-driving dust species. Conclusions. To reproduce the observed photometric variations in (V-K) and (J-K) both detailed and parameterized models suggest that the wind-driving dust materials have to be quite transparent in the visual and near-IR. Consequently, strong candidates for outflows driven by photon scattering on dust grains are Mg2SiO4, MgSiO3, and potentially SiO2.

  • 40.
    Bladh, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics, Theoretical Astrophysics.
    Susanne, Höfner
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Aringer, Bernhard
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Exploring wind-driving dust species in cool luminous giants III: Wind models for M-type AGB stars2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 575, article id A105Article in journal (Refereed)
  • 41. Blanco-Cuaresma, S.
    et al.
    Soubiran, C.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Asplund, M.
    Carraro, G.
    Costado, M. T.
    Feltzing, S.
    Gonzalez-Hernandez, J. I.
    Jimenez-Esteban, F.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Marino, A. F.
    Montes, D.
    San Roman, I.
    Tabernero, H. M.
    Tautvaisiene, G.
    Testing the chemical tagging technique with open clusters2015In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 577, article id A47Article in journal (Refereed)
    Abstract [en]

    Context. Stars are born together from giant molecular clouds and, if we assume that the priors were chemically homogeneous and well-mixed, we expect them to share the same chemical composition. Most of the stellar aggregates are disrupted while orbiting the Galaxy and most of the dynamic information is lost, thus the only possibility of reconstructing the stellar formation history is to analyze the chemical abundances that we observe today. Aims. The chemical tagging technique aims to recover disrupted stellar clusters based merely on their chemical composition. We evaluate the viability of this technique to recover co-natal stars that are no longer gravitationally bound. Methods. Open clusters are co-natal aggregates that have managed to survive together. We compiled stellar spectra from 31 old and intermediate-age open clusters, homogeneously derived atmospheric parameters, and 17 abundance species, and applied machine learning algorithms to group the stars based on their chemical composition. This approach allows us to evaluate the viability and efficiency of the chemical tagging technique. Results. We found that stars at different evolutionary stages have distinct chemical patterns that may be due to NLTE effects, atomic diffusion, mixing, and biases. When separating stars into dwarfs and giants, we observed that a few open clusters show distinct chemical signatures while the majority show a high degree of overlap. This limits the recovery of co-natal aggregates by applying the chemical tagging technique. Nevertheless, there is room for improvement if more elements are included and models are improved.

  • 42.
    Bodewits, D.
    et al.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA..
    Lara, L. M.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    A'Hearn, M. F.
    Univ Maryland, Dept Astron, College Pk, MD 20742 USA.;Akad Wissensch Gottingen, D-37077 Gottingen, Germany..
    La Forgia, F.
    Univ Padua, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Gicquel, A.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Kovacs, G.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Knollenberg, J.
    Deutsch Zentrum Luft & Raumfahrt DLR, Inst Planetenforsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Lazzarin, M.
    Univ Padua, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Lin, Z. -Y
    Shi, X.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Snodgrass, C.
    Open Univ, Dept Phys Sci, Planetary & Space Sci, Milton Keynes MK7 6AA, Bucks, England..
    Tubiana, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Sierks, H.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Barbieri, C.
    Univ Padua, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Lamy, P. L.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Rodrigo, R.
    CSIC, INTA, Ctr Astrobiol, E-28850 Madrid, Spain.;Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland..
    Koschny, D.
    European Space Res & Technol Ctr ESA, Sci Support Off, Keplerlaan 1,Postbus 299, NL-2201 AZ Noordwijk, Netherlands..
    Rickman, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Keller, H. U.
    Tech Univ Carolo Wilhelmina Braunschweig, IGEP, Mendelssohnstr 3, D-38106 Braunschweig, Germany..
    Barucci, M. A.
    Univ Paris Diderot, Univ Pierre & Marie Curie, CNRS, LESIA Observ Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Bertaux, J. -L
    Bertini, I.
    Univ Padua, Ctr Ateneo Studi & Attivita Spaziali Giuseppe Col, Via Venezia 15, I-35131 Padua, Italy..
    Boudreault, S.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Cremonese, G.
    Osserv Astron Padova, INAF, Vicolo Osservatorio 5, I-35122 Padua, Italy..
    Da Deppo, V.
    CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy..
    Davidsson, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Debei, S.
    Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy..
    De Cecco, M.
    Univ Trento, Via Sommar 9, I-38123 Trento, Italy..
    Fornasier, S.
    Univ Paris Diderot, Univ Pierre & Marie Curie, CNRS, LESIA Observ Paris, 5 Pl J Janssen, F-92195 Meudon, France..
    Fulle, M.
    Osserv Astron Trieste, INAF, Via Tiepolo 11, I-34014 Trieste, Italy..
    Groussin, O.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Gutierrez, P. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Guettler, C.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Hviid, S. F.
    Deutsch Zentrum Luft & Raumfahrt DLR, Inst Planetenforsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Ip, W. -H
    Jorda, L.
    Aix Marseille Univ, CNRS, LAM, UMR 7326, F-13388 Marseille, France..
    Kramm, J. -R
    Kuehrt, E.
    Deutsch Zentrum Luft & Raumfahrt DLR, Inst Planetenforsch, Rutherfordstr 2, D-12489 Berlin, Germany..
    Kuppers, M.
    European Space Astron Ctr ESA, Operat Dept, POB 78, E-28691 Villanueva De La Canada, Madrid, Spain..
    Lopez-Moreno, J. J.
    CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain..
    Marzari, F.
    Univ Padua, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy..
    Naletto, G.
    Univ Padua, Dept Phys & Astron, Vicolo Osservatorio 3, I-35122 Padua, Italy.;CNR, IFN UOS Padova LUXOR, Via Trasea 7, I-35131 Padua, Italy.;Univ Padua, Dept Informat Engn, Via Gradenigo 6-B, I-35131 Padua, Italy..
    Oklay, N.
    Max Planck Inst Sonnensyst Forsch, Justus von Liebig Weg 3, D-37077 Gottingen, Germany..
    Thomas, N.
    Univ Bern, Inst Phys, Sidlerstr 5, CH-3012 Bern, Switzerland.;Univ Bern, Ctr Space & Habitabil, CH-3012 Bern, Switzerland..
    Toth, I.
    MTA CSFK Konkoly Observ, Konkoly Thege M Ut 15-17, HU-1525 Budapest, Hungary..
    Vincent, J. -B
    Changes in the physical environment of the inner coma of 67p/churyumov-gerasimenko with decreasing heliocentric distance2016In: Astronomical Journal, ISSN 0004-6256, E-ISSN 1538-3881, Vol. 152, no 5, article id 130Article in journal (Refereed)
    Abstract [en]

    The Wide Angle Camera of the OSIRIS instrument on board the Rosetta spacecraft is equipped with several narrow-band filters that are centered on the emission lines and bands of various fragment species. These are used to determine the evolution of the production and spatial distribution of the gas in the inner coma of comet 67P with time and heliocentric distance, here between 2.6 and 1.3 au pre-perihelion. Our observations indicate that the emission observed in the OH, OI, CN, NH, and NH2 filters is mostly produced by dissociative electron impact excitation of different parent species. We conclude that CO2 rather than H2O is a significant source of the [OI] 630 nm emission. A strong plume-like feature observed in the CN and OI filters is present throughout our observations. This plume is not present in OH emission and indicates a local enhancement of the CO2/H2O ratio by as much as a factor of 3. We observed a sudden decrease in intensity levels after 2015 March, which we attribute to decreased electron temperatures in the first few kilometers above the surface of the nucleus.

  • 43. Bonifacio, P.
    et al.
    Caffau, E.
    Ludwig, H. -G
    Steffen, M.
    Castelli, F.
    Gallagher, A. J.
    Kučinskas, A.
    Prakapavičius, D.
    Cayrel, R.
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Plez, B.
    Homeier, D.
    Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours. I. Grids of 3D corrections in the UBVRI, 2MASS, HIPPARCOS, Gaia, and SDSS systems2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 611Article in journal (Refereed)
  • 44. Bonifacio, P.
    et al.
    Caffau, E.
    Ludwig, H. -G
    Steffen, M.
    Castelli, F.
    Gallagher, A. J.
    Prakapavičius, D.
    Kučinskas, A.
    Cayrel, R.
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Plez, B.
    Homeier, D.
    Using CO5BOLD models to predict the effects of granulation on colours .2017In: MEMORIE della Società Astronomica Italiana, ISSN 0037-8720, E-ISSN 1824-016X, Vol. 88Article in journal (Other academic)
  • 45. Boyajian, T.
    et al.
    von Braun, K.
    Feiden, Gregory
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Huber, D.
    Basu, S.
    Demarque, P.
    Fischer, D. A.
    Schaefer, G.
    Mann, A. W.
    White, T. R.
    Maestro, V.
    Brewer, J.
    Lamell, C. B.
    Spada, F.
    López-Morales, M.
    Ireland, M.
    Farrington, C.
    van Belle, G. T.
    Kane, S. R.
    Jones, J.
    ten Brummelaar, T. A.
    Ciardi, D. R.
    McAlister, H. A.
    Ridgway, S.
    Goldfinger, P. J.
    Turner, N. H.
    Sturmann, L.
    Stellar diameters and temperatures - VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs2015In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 447, no 1, p. 846-857Article in journal (Refereed)
    Abstract [en]

    We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be thetaLD = 0.3848 +/- 0.0055 and 0.2254 +/- 0.0072 milliarcsec for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion's orbital motion from high resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (Teff = 4875 +/- 43, 6093 +/- 103 K), stellar linear radii (R* = 0.805 +/- 0.016, 1.203 +/- 0.061 Rsun), mean stellar densities (rho* = 1.62 +/- 0.11, 0.58 +/- 0.14 rhosun), planetary radii (Rp = 1.216 +/- 0.024, 1.451 +/- 0.074 RJup), and mean planetary densities (rhop = 0.605 +/- 0.029, 0.196 +/- 0.033 rhoJup) for HD 189733 b and HD 209458 b, respectively. The stellar parameters for HD 209458, a F9 dwarf, are consistent with indirect estimates derived from spectroscopic and evolutionary modeling. However, we find that models are unable to reproduce the observational results for the K2 dwarf, HD 189733. We show that, for stellar evolutionary models to match the observed stellar properties of HD 189733, adjustments lowering the solar-calibrated mixing length parameter from 1.83 to 1.34 need to be employed.

  • 46.
    Brown, A. G. A.
    et al.
    Leiden Univ, Leiden Observ, Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Vallenari, A.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Prusti, T.
    European Space Res & Technol Ctr ESA ESTEC, Sci Support Off, Directorate Sci, Keplerlaan 1, NL-2201AZ Noordwijk, Netherlands.
    de Bruijne, J. H. J.
    European Space Res & Technol Ctr ESA ESTEC, Sci Support Off, Directorate Sci, Keplerlaan 1, NL-2201AZ Noordwijk, Netherlands.
    Babusiaux, C.
    Univ Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France;Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Bailer-Jones, C. A. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Biermann, M.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Evans, D. W.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Eyer, L.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Jansen, F.
    European Space Res & Technol Ctr ESA ESTEC, Miss Operat Div, Operat Dept, Directorate Sci, Keplerlaan 1, NL-2201 AZ Noordwijk, Netherlands.
    Jordi, C.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Klioner, S. A.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Lammers, U.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Lindegren, L.
    Lund Univ, Lund Observ, Dept Astron & Theoret Phys, Box 43, S-22100 Lund, Sweden.
    Luri, X.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Mignard, F.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Panem, C.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Pourbaix, D.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium;FRS FNRS, Rue Egmont 5, B-1000 Brussels, Belgium.
    Randich, S.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Sartoretti, P.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Siddiqui, H. I.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Soubiran, C.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    van Leeuwen, F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Walton, N. A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Arenou, F.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Bastian, U.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Cropper, M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Drimmel, R.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Katz, D.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Lattanzi, M. G.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Bakker, J.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Cacciari, C.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Castaneda, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Chaoul, L.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Cheek, N.
    Serco Gest Negocios ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    De Angeli, F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Fabricius, C.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Guerra, R.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Holl, B.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Masana, E.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Messineo, R.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Mowlavi, N.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Nienartowicz, K.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Panuzzo, P.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Portell, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Riello, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Seabroke, G. M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Tanga, P.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Thevenin, F.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Gracia-Abril, G.
    ESAC, Gaia DPAC Project Off, Camino Bajo Castillo S-N, Madrid 28692, Spain;Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Comoretto, G.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Garcia-Reinaldos, M.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Teyssier, D.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Altmann, M.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France;Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Andrae, R.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Audard, M.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Bellas-Velidis, I.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Benson, K.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Berthier, J.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France.
    Blomme, R.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Burgess, P.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Busso, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Carry, B.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France;Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Cellino, A.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Clementini, G.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Clotet, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Creevey, O.
    Univ Paris XI, CNRS, UMR 8617, Inst Astrophys Spatiale, Batiment 121, F-91405 Orsay, France;Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Davidson, M.
    Univ Edinburgh, Inst Astron, Royal Observ, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    De Ridder, J.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Delchambre, L.
    Univ Liege, Inst Astrophys & Geophys, 19c,Allee 6 Aout, B-4000 Liege, Belgium.
    Dell'Oro, A.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Ducourant, C.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Fernandez-Hernandez, J.
    ATG Europe ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Fouesneau, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Fremat, Y.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Galluccio, L.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Garcia-Torres, M.
    Univ Pablo Olavide, Area Lenguajes Sistemas Informat, Ctra Utrera,Km 1, Seville 41013, Spain.
    Gonzalez-Nunez, J.
    Univ Vigo, ETSE Telecomun, Campus Lagoas Marcosende, Vigo 36310, Galicia, Spain;Serco Gest Negocios ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Gonzalez-Vidal, J. J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Gosset, E.
    Univ Liege, Inst Astrophys & Geophys, 19c,Allee 6 Aout, B-4000 Liege, Belgium;FRS FNRS, Rue Egmont 5, B-1000 Brussels, Belgium.
    Guy, L. P.
    Large Synopt Survey Telescope, 950 N Cherry Ave, Tucson, AZ 85719 USA;Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Halbwachs, J. -L
    Hambly, N. C.
    Univ Edinburgh, Inst Astron, Royal Observ, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Harrison, D. L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Cambridge, Kavli Inst Cosmol, Madingley Rd, Cambridge CB3 0HA, England.
    Hernandez, J.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Hestroffer, D.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France.
    Hodgkin, S. T.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Hutton, A.
    Aurora Technol ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Jasniewicz, G.
    Univ Montpellier, Lab Univ & Particules Montpellier, Pl Eugene Bataillon,CC72, F-34095 Montpellier 5, France.
    Jean-Antoine-Piccolo, A.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Jordan, S.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Korn, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Krone-Martins, A.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Lanzafame, A. C.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy;Univ Catania, Dipartimento Fis & Astron, Sez Astrofis, Via S Sofia 78, I-95123 Catania, Italy.
    Lebzelter, T.
    Univ Vienna, Dept Astrophys, Turkenschanz Str 17, A-1180 Vienna, Austria.
    Loeffler, W.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Manteiga, M.
    Univ A Coruna, CITIC Astron & Astrophys, Campus Elvina S-N, La Coruna 15071, Spain;Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Marrese, P. M.
    INAF Osservatorio Astron Roma, Via Frascati 33, I-00078 Rome, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Martin-Fleitas, J. M.
    Aurora Technol ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Moitinho, A.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Mora, A.
    Aurora Technol ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Muinonen, K.
    Univ Helsinki, Dept Phys, POB 64, FIN-00014 Helsinki, Finland;Finnish Geospatial Res Inst FGI, Geodeetinrinne 2, Masala 02430, Finland.
    Osinde, J.
    Isdefe ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Pancino, E.
    ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy;INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Pauwels, T.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Petit, J. -M
    Recio-Blanco, A.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Richards, P. J.
    Rutherford Appleton Lab, STFC, Harwell OX11 0QX, Didcot, England.
    Rimoldini, L.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Robin, A. C.
    Univ Bourgogne Franche Comte, CNRS, Inst UTINAM UMR6213, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Sarro, L. M.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Siopis, C.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium.
    Smith, M.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Sozzetti, A.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Sueveges, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Torra, J.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    van Reeven, W.
    Aurora Technol ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Abbas, U.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Aramburu, A. Abreu
    Elecnor Deimos Space ESA ESAC, Camino Bajo Castillo S-N,Urbanizac Villafranca Ca, Madrid 28692, Spain.
    Accart, S.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Aerts, C.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Altavilla, G.
    INAF Osservatorio Astron Roma, Via Frascati 33, I-00078 Rome, Italy;INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Alvarez, M. A.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Alvarez, R.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Alves, J.
    Univ Vienna, Dept Astrophys, Turkenschanz Str 17, A-1180 Vienna, Austria.
    Anderson, R. I.
    European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching, Germany;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Andrei, A. H.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France;OV UFRJ, Ladeira Pedro Antonio 43, BR-20080090 Rio De Janeiro, Brazil;ON MCT, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, Brazil.
    Anglada Varela, E.
    ATG Europe ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Antiche, E.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Antoja, T.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain;European Space Res & Technol Ctr ESA ESTEC, Sci Support Off, Directorate Sci, Keplerlaan 1, NL-2201AZ Noordwijk, Netherlands.
    Arcay, B.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Astraatmadja, T. L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Carnegie Inst Sci, Dept Terr Magnetism, 5241 Broad Branch Rd,NW, Washington, DC 20015 USA.
    Bach, N.
    Aurora Technol ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Baker, S. G.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Balaguer-Nunez, L.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Balm, P.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Barache, C.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France.
    Barata, C.
    Barbato, D.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin, Italy.
    Barblan, F.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Barklem, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Barrado, D.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N,Villanueva Canada, Madrid 28692, Spain.
    Barros, M.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Barstow, M. A.
    Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England;Univ Leicester, Leicester Inst Space & Earth Observat, Univ Rd, Leicester LE1 7RH, Leics, England.
    Bartholome Munoz, S.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Bassilana, J. -L
    Becciani, U.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Bellazzini, M.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Berihuete, A.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France;Univ Cadiz, Dept Estadist, Calle Republ Arabe Saharawi S-N, Cadiz 11510, Spain;INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Bertone, S.
    Bern Univ, Astron Inst, Sidlerstr 5, CH-3012 Bern, Switzerland;Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France;INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Bianchi, L.
    EURIX Srl, Corso Vittorio Emanuele 2 61, I-10128 Turin, Italy.
    Bienayme, O.
    Univ Strasbourg, Observ Astron Strasbourg, 11 Rue Univ, F-67000 Strasbourg, France.
    Blanco-Cuaresma, S.
    Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA;Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Boch, T.
    Univ Strasbourg, Observ Astron Strasbourg, 11 Rue Univ, F-67000 Strasbourg, France.
    Boeche, C.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bombrun, A.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Borrachero, R.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Bossini, D.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Bouquillon, S.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France.
    Bourda, G.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Bragaglia, A.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Bramante, L.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Breddels, M. A.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Bressan, A.
    Scuola Int Super Studi Avanzati, SISSA, Via Bonomea 265, I-34136 Trieste, Italy.
    Brouillet, N.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Bruesemeister, T.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Brugaletta, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Bucciarelli, B.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Burlacu, A.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Busonero, D.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Butkevich, A. G.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Buzzi, R.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Caffau, E.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Cancelliere, R.
    Univ Turin, Dept Comp Sci, Corso Svizzera 185, I-10149 Turin, Italy.
    Cannizzaro, G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Cantat-Gaudin, T.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy;Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Carballo, R.
    Univ Cantabria, Dept Matemat Aplicada & Ciencias Computac, ETS Ingenieros Caminos Canales & Puertos, Avda Castros S-N, E-39005 Santander, Spain.
    Carlucci, T.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France.
    Carrasco, J. M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Casamiquela, L.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Castellani, M.
    INAF Osservatorio Astron Roma, Via Frascati 33, I-00078 Rome, Italy.
    Castro-Ginard, A.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Charlot, P.
    Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N,Allee Geoffroy St Hilaire, F-33615 Pessac, France.
    Chemin, L.
    Univ Antofagasta, Unidad Astron, Ave Angamos 601, Antofagasta 1270300, Chile.
    Chiavassa, A.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Cocozza, G.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Costigan, G.
    Leiden Univ, Leiden Observ, Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Cowell, S.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Crifo, F.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Crosta, M.
    Crowley, C.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Cuypers, J.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Dafonte, C.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Damerdji, Y.
    Univ Liege, Inst Astrophys & Geophys, 19c,Allee 6 Aout, B-4000 Liege, Belgium;CRAAG, Route Observ,Bp 63, Bouzareah 16340, Algeria.
    Dapergolas, A.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    David, P.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France.
    David, M.
    Univ Antwerp, Onderzoeksgroep Toegepaste Wiskunde, Middelheimlaan 1, B-2020 Antwerp, Belgium.
    de Laverny, P.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    De Luise, F.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    De March, R.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    de Martino, D.
    de Souza, R.
    Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226,Cidade Univ, BR-05508900 Sao Paulo, Brazil.
    de Torres, A.
    ESA ESAC, HE Space Operat BV, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Debosscher, J.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    del Pozo, E.
    Aurora Technol ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Delbo, M.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Delgado, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Delgado, H. E.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Di Matteo, P.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Diakite, S.
    Univ Bourgogne Franche Comte, CNRS, Inst UTINAM UMR6213, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Diener, C.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Distefano, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Dolding, C.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Drazinos, P.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Duran, J.
    Isdefe ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Edvardsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Enke, H.
    Leibniz Inst Astrophys Potsdam AIP, Stern Warte 16, D-14482 Potsdam, Germany.
    Eriksson, Kjell
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Esquej, P.
    ESA ESAC, RHEA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Eynard Bontemps, G.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Fabre, C.
    CNES Ctr Spatial Toulouse, ATOS, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Fabrizio, M.
    INAF Osservatorio Astron Roma, Via Frascati 33, I-00078 Rome, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Faigler, S.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    Falcao, A. J.
    CTS, UNINOVA, Campus FCT UNL,Monte Caparica, P-2829516 Caparica, Portugal.
    Farras Casas, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Federici, L.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Fedorets, G.
    Univ Helsinki, Dept Phys, POB 64, FIN-00014 Helsinki, Finland.
    Fernique, P.
    Univ Strasbourg, Observ Astron Strasbourg, 11 Rue Univ, F-67000 Strasbourg, France.
    Figueras, F.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Filippi, F.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Findeisen, K.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Fonti, A.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Fraile, E.
    ESA ESAC, RHEA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Fraser, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Coll Dublin, Sch Phys, OBrien Ctr Sci North, Dublin 4, Ireland.
    Frezouls, B.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Gai, M.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Galleti, S.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Garabato, D.
    Univ A Coruna, CITIC, Dept Comp Sci, Campus Elvina S-N, La Coruna 15071, Spain.
    Garcia-Sedano, F.
    UNED, Dept Inteligencia Artificial, C Juan Rosal 16, Madrid 28040, Spain.
    Garofalo, A.
    Univ Bologna, Dipartimento Fis & Astron, Via Piero Gobetti 93-2, I-40129 Bologna, Italy;INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Garralda, N.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Gavel, Alvin
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Gavras, P.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece;Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France;Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Gerssen, J.
    Leibniz Inst Astrophys Potsdam AIP, Stern Warte 16, D-14482 Potsdam, Germany.
    Geyer, R.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Giacobbe, P.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Gilmore, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Girona, S.
    Ctr Nacl Super Comput, Barcelona Supercomputing Ctr, C Jordi Girona 29,Ed Nexus II, Barcelona 08034, Spain.
    Giuffrida, G.
    INAF Osservatorio Astron Roma, Via Frascati 33, I-00078 Rome, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Glass, F.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Gomes, M.
    Univ Lisbon, CENTRA, FCUL, Campo Grande,Edif C8, P-1749016 Lisbon, Portugal.
    Granvik, M.
    Univ Helsinki, Dept Phys, POB 64, FIN-00014 Helsinki, Finland;Lulea Univ Technol, Dept Comp Sci Elect & Space Engn, Box 848, S-98128 Kiruna, Sweden.
    Gueguen, A.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France;Max Planck Inst Extraterrestrial Phys, High Energy Grp, Giessenbachstr, D-85741 Garching, Germany.
    Guerrier, A.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Guiraud, J.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Gutierrez-Sanchez, R.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Haigron, R.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Hatzidimitriou, D.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece;Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Hauser, M.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany;Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Haywood, M.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Heiter, Ulrike
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Helmi, A.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Heu, J.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Hilger, T.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Hobbs, D.
    Lund Univ, Lund Observ, Dept Astron & Theoret Phys, Box 43, S-22100 Lund, Sweden.
    Hofmann, W.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Holland, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Huckle, H. E.
    Univ Coll London, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
    Hypki, A.
    Adam Mickiewicz Univ, Astron Observ Inst, Fac Phys, Sloneczna 36, PL-60286 Poznan, Poland;Leiden Univ, Leiden Observ, Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Icardi, V.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Janssen, K.
    Leibniz Inst Astrophys Potsdam AIP, Stern Warte 16, D-14482 Potsdam, Germany.
    Jevardat de Fombelle, G.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Jonker, P. G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Juhasz, A. L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary;Eotvos Lorand Univ, Egyet Ter 1-3, H-1053 Budapest, Hungary.
    Julbe, F.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Karampelas, A.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece;Amer Community Schools Athens, 129 Aghias Paraskevis Ave & Kazantzaki St, Athens 15234, Greece.
    Kewley, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Klar, J.
    Leibniz Inst Astrophys Potsdam AIP, Stern Warte 16, D-14482 Potsdam, Germany.
    Kochoska, A.
    Villanova Univ, Dept Astrophys & Planetary Sci, 800 E Lancaster Ave, Villanova, PA 19085 USA;Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia.
    Kohley, R.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Kolenberg, K.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium;Univ Antwerp, Phys Dept, Groenenborgerlaan 171, B-2020 Antwerp, Belgium;Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA.
    Kontizas, M.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Kontizas, E.
    Natl Observ Athens I Metaxa & Vas Pavlou Palaia P, Athens 15236, Greece.
    Koposov, S. E.
    Carnegie Mellon Univ, McWilliams Ctr Cosmol, Dept Phys, 5000 Forbes Ave, Pittsburgh, PA 15213 USA;Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Kordopatis, G.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Kostrzewa-Rutkowska, Z.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;SRON Netherlands Inst Space Res, Sorbonnelaan 2, NL-3584CA Utrecht, Netherlands.
    Koubsky, P.
    Acad Sci Czech Republ, Astron Inst, Fricova 298, Ondrejov 25165, Czech Republic.
    Lambert, S.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France.
    Lanza, A. F.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Lasne, Y.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Lavigne, J. -B
    Le Fustec, Y.
    CNES, Telespazio, Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Le Poncin-Lafitte, C.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France.
    Lebreton, Y.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France;Univ Rennes 1, Inst Phys Rennes, F-35042 Rennes, France.
    Leccia, S.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Leclerc, N.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Lecoeur-Taibi, I.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Lenhardt, H.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Leroux, F.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Liao, S.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Chinese Acad Sci, Shanghai Astron Observ, 80 Nandan Rd, Shanghai 200030, Peoples R China;Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China.
    Licata, E.
    EURIX Srl, Corso Vittorio Emanuele 2 61, I-10128 Turin, Italy.
    Lindstrom, H. E. P.
    Univ Copenhagen, Niels Bohr Inst, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark;DXC Technol, Retortvej 8, DK-2500 Valby, Denmark.
    Lister, T. A.
    Las Cumbres Observ, 6740 Cortona Dr Suite 102, Goleta, CA 93117 USA.
    Livanou, E.
    Univ Athens, Dept Astrophys Astron & Mech, Panepistimiopolis, Athens 15783, Greece.
    Lobel, A.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    Lopez, M.
    ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N,Villanueva Canada, Madrid 28692, Spain.
    Managau, S.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Mann, R. G.
    Univ Edinburgh, Inst Astron, Royal Observ, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Mantelet, G.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Marchal, O.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Marchant, J. M.
    Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England.
    Marconi, M.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Marinoni, S.
    INAF Osservatorio Astron Roma, Via Frascati 33, I-00078 Rome, Italy;ASI, Space Sci Data Ctr, Via Politecn SNC, I-00133 Rome, Italy.
    Marschalko, G.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary;Univ Szeged, Baja Observ, Szegedi Ut 3-70, H-6500 Baja, Hungary.
    Marshall, D. J.
    Univ Paris Diderot, CNRS, Lab AIM, IRFU Serv Astrophys CEA DSM, Bat 709,CEA Saclay, F-91191 Gif Sur Yvette, France.
    Martino, M.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Marton, G.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Mary, N.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Massari, D.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Matijevic, G.
    Leibniz Inst Astrophys Potsdam AIP, Stern Warte 16, D-14482 Potsdam, Germany.
    Mazeh, T.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    McMillan, P. J.
    Lund Univ, Lund Observ, Dept Astron & Theoret Phys, Box 43, S-22100 Lund, Sweden.
    Messina, S.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Michalik, D.
    Lund Univ, Lund Observ, Dept Astron & Theoret Phys, Box 43, S-22100 Lund, Sweden.
    Millar, N. R.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Molina, D.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Molinaro, R.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Molnar, L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Montegriffo, P.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Mor, R.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Morbidelli, R.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Morel, T.
    Univ Liege, Inst Astrophys & Geophys, 19c,Allee 6 Aout, B-4000 Liege, Belgium.
    Morris, D.
    Univ Edinburgh, Inst Astron, Royal Observ, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Mulone, A. F.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Muraveva, T.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Musella, I.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Nelemans, G.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Nicastro, L.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Noval, L.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    O'Mullane, W.
    Large Synopt Survey Telescope, 950 N Cherry Ave, Tucson, AZ 85719 USA;European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Ordenovic, C.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Ordonez-Blanco, D.
    Univ Geneva, Dept Astron, Chemin Ecogia 16, CH-1290 Versoix, Switzerland.
    Osborne, P.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Pagani, C.
    Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England;Univ Leicester, Leicester Inst Space & Earth Observat, Univ Rd, Leicester LE1 7RH, Leics, England.
    Pagano, I.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Pailler, F.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Palacin, H.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Palaversa, L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Panahi, A.
    Tel Aviv Univ, Sch Phys & Astron, IL-6997801 Tel Aviv, Israel.
    Pawlak, M.
    Univ Warsaw Observ, Al Ujazdowskie 4, PL-00478 Warsaw, Poland;Charles Univ Prague, Inst Theoret Phys, Fac Math & Phys, Prague, Czech Republic.
    Piersimoni, A. M.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    Pineau, F. -X
    Plachy, E.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Plum, G.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Poggio, E.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy;Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin, Italy.
    Poujoulet, E.
    CNES Ctr Spatial Toulouse, AKKA, 18 Ave Edouard Belin, F-314019 Toulouse, France.
    Prsa, A.
    Villanova Univ, Dept Astrophys & Planetary Sci, 800 E Lancaster Ave, Villanova, PA 19085 USA.
    Pulone, L.
    INAF Osservatorio Astron Roma, Via Frascati 33, I-00078 Rome, Italy.
    Racero, E.
    Serco Gest Negocios ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Ragaini, S.
    INAF, Osservatorio Astrofis & Sci Spazio Bologna, Via Piero Gobetti 93-3, I-40129 Bologna, Italy.
    Rambaux, N.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France.
    Ramos-Lerate, M.
    ESA ESAC, Vitrociset Belgium, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Regibo, S.
    Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Reyle, C.
    Univ Bourgogne Franche Comte, CNRS, Inst UTINAM UMR6213, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Riclet, F.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Ripepi, V.
    INAF, Osservatorio Astron Capodimonte, Via Moiariello 16, I-80131 Naples, Italy.
    Riva, A.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Rivard, A.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Rixon, G.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Roegiers, T.
    ESA ESTEC, HE Space Operat BV, Keplerlaan 1, NL-2201AZ Noordwijk, Netherlands.
    Roelens, M.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Romero-Gomez, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Rowell, N.
    Univ Edinburgh, Inst Astron, Royal Observ, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Royer, F.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Ruiz-Dern, L.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Sadowski, G.
    Univ Libre Bruxelles, Inst Astron & Astrophys, CP 226,Blvd Triomphe, B-1050 Brussels, Belgium.
    Sagrista Selles, T.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Sahlmann, J.
    European Space Astron Ctr ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain;Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA.
    Salgado, J.
    ESA ESAC, QUASAR Sci Resources, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Salguero, E.
    ATG Europe ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Sanna, N.
    INAF Osservatorio Astrofis Arcetri, Largo Enrico Fermi 5, I-50125 Florence, Italy.
    Santana-Ros, T.
    Adam Mickiewicz Univ, Astron Observ Inst, Fac Phys, Sloneczna 36, PL-60286 Poznan, Poland.
    Sarasso, M.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Savietto, H.
    Fork Res, Rua Cruzado Osberno,Lt 1,9 Esq, Lisbon, Portugal.
    Schultheis, M.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Sciacca, E.
    INAF, Osservatorio Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy.
    Segol, M.
    CNES Ctr Spatial Toulouse, APAVE SUDEUROPE SAS, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Segovia, J. C.
    Serco Gest Negocios ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Segransan, D.
    Univ Geneva, Dept Astron, Chemin Maillettes 51, CH-1290 Versoix, Switzerland.
    Shih, I-C
    Siltala, L.
    Nord Optic Telescope, Rambla Jose Ana Fernandez Perez 7, Brena Baja 38711, Spain;Univ Helsinki, Dept Phys, POB 64, FIN-00014 Helsinki, Finland.
    Silva, A. F.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
    Smart, R. L.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Smith, K. W.
    Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany.
    Solano, E.
    Spanish Virtual Observ, Santander, Spain;ESA ESAC, Dept Astrofis, Ctr Astrobiol, CSIC INTA, Camino Bajo Castillo S-N,Villanueva Canada, Madrid 28692, Spain.
    Solitro, F.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Sordo, R.
    INAF, Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua, Italy.
    Soria Nieto, S.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Souchay, J.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France.
    Spagna, A.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Spoto, F.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France;Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Stampa, U.
    Heidelberg Univ, Astron Rechen Inst, Zentrum Astron, Monchhofstr 12-14, D-69120 Heidelberg, Germany.
    Steele, I. A.
    Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England.
    Steidelmueller, H.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Stephenson, C. A.
    ESA ESAC, Telespazio Vega UK Ltd, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Stoev, H.
    INAF, Fdn Galileo Galilei, Rambla Jose Ana Fernandez Perez 7, Santa Cruz de Tenerife 38712, Spain.
    Suess, F. F.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Surdej, J.
    Univ Liege, Inst Astrophys & Geophys, 19c,Allee 6 Aout, B-4000 Liege, Belgium.
    Szabados, L.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Szegedi-Elek, E.
    Hungarian Acad Sci, Konkoly Observ, Res Ctr Astron & Earth Sci, Konkoly Thege Miklos Ut 15-17, H-1121 Budapest, Hungary.
    Tapiador, D.
    Univ Complutense Madrid, Dept Arquitectura Computadores & Automat, Fac Informat, C Prof Jose Garcia Santesmases S-N, E-28040 Madrid, Spain;ESA ESAC, INSA, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Taris, F.
    Univ PSL, CNRS, SYRTE, Observ Paris, LNE,61 Ave Observ, F-75014 Paris, France.
    Tauran, G.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Taylor, M. B.
    Univ Bristol, H H Wills Phys Lab, Tyndall Ave, Bristol BS8 1TL, Avon, England.
    Teixeira, R.
    Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226,Cidade Univ, BR-05508900 Sao Paulo, Brazil.
    Terrett, D.
    Rutherford Appleton Lab, STFC, Harwell OX11 0QX, Didcot, England.
    Teyssandier, P.
    Thuillot, W.
    Univ Lille, Sorbonne Univ, IMCCE, Observ Paris,Univ PSL, 77 Ave Denfert Rochereau, F-75014 Paris, France.
    Titarenko, A.
    Univ Cote dAzur, CNRS, Observ Cote dAzur, Lab Lagrange,Bd Observ, CS 34229, F-06304 Nice 4, France.
    Torra Clotet, F.
    IEEC, Gran Capita 2-4, Barcelona 08034, Spain.
    Turon, C.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Ulla, A.
    Univ Vigo, Appl Phys Dept, Vigo 36310, Spain.
    Utrilla, E.
    Aurora Technol ESA ESAC, Camino Bajo Castillo S-N, Madrid 28692, Spain.
    Uzzi, S.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Vaillant, M.
    Thales Serv CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Valentini, G.
    INAF, Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy.
    Valette, V.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    van Elteren, A.
    Leiden Univ, Leiden Observ, Bohrweg 2, NL-2333 CA Leiden, Netherlands.
    Van Hemelryck, E.
    Royal Observ Belgium, Ringlaan 3, B-1180 Brussels, Belgium.
    van Leeuwen, M.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Vaschetto, M.
    ALTEC, Corso Marche 79, I-10146 Turin, Italy.
    Vecchiato, A.
    INAF, Osservatorio Astrofis Torino, Via Osservatorio 20, I-10025 Pino Torinese, Italy.
    Veljanoski, J.
    Univ Groningen, Kapteyn Astron Inst, Landleven 12, NL-9747 AD Groningen, Netherlands.
    Viala, Y.
    Univ PSL, CNRS, GEPI, Observ Paris, 5 Pl Jules Janssen, F-92190 Meudon, France.
    Vicente, D.
    Ctr Nacl Super Comput, Barcelona Supercomputing Ctr, C Jordi Girona 29,Ed Nexus II, Barcelona 08034, Spain.
    Vogt, S.
    ESA ESTEC, HE Space Operat BV, Keplerlaan 1, NL-2201AZ Noordwijk, Netherlands.
    von Essen, C.
    Aarhus Univ, Stellar Astrophys Ctr, Dept Phys & Astron, 120 Ny Munkegade,Bldg 1520, DK-8000 Aarhus, Denmark.
    Voss, H.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Votruba, V.
    Acad Sci Czech Republ, Astron Inst, Fricova 298, Ondrejov 25165, Czech Republic.
    Voutsinas, S.
    Univ Edinburgh, Inst Astron, Royal Observ, Blackford Hill, Edinburgh EH9 3HJ, Midlothian, Scotland.
    Walmsley, G.
    CNES Ctr Spatial Toulouse, 18 Ave Edouard Belin, F-31401 Toulouse 9, France.
    Weiler, M.
    Univ Barcelona, Inst Ciencies Cosmos, IEEC UB, E-08028 Barcelona, Spain.
    Wertz, O.
    Univ Bonn, Argelander Inst Astron, Hugel 71, D-53121 Bonn, Germany.
    Wevers, T.
    Radboud Univ Nijmegen, Dept Astrophys, IMAPP, POB 9010, NL-6500 GL Nijmegen, Netherlands;Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Wyrzykowski, L.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England;Univ Warsaw Observ, Al Ujazdowskie 4, PL-00478 Warsaw, Poland.
    Yoldas, A.
    Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England.
    Zerjal, M.
    Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia;Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 2611, Australia.
    Ziaeepour, H.
    Univ Bourgogne Franche Comte, CNRS, Inst UTINAM UMR6213, OSU THETA Franche Comte Bourgogne, F-25000 Besancon, France.
    Zorec, J.
    Sorbonne Univ, CNRS, Inst Astrophys Paris, UPMC Univ Paris 6,UMR 7095, 98 Bis Bd Arago, F-75014 Paris, France.
    Zschocke, S.
    Tech Univ Dresden, Lohrmann Observ, Mommsenstr 13, D-01062 Dresden, Germany.
    Zucker, S.
    Tel Aviv Univ, Dept Geosci, IL-6997801 Tel Aviv, Israel.
    Zurbach, C.
    Univ Montpellier, Lab Univ & Particules Montpellier, Pl Eugene Bataillon,CC72, F-34095 Montpellier 5, France.
    Zwitter, T.
    Univ Ljubljana, Fac Math & Phys, Jadranska Ulica 19, Ljubljana 1000, Slovenia.
    Gaia Data Release 2 Summary of the contents and survey properties2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id A1Article in journal (Refereed)
    Abstract [en]

    Context. We present the second Gaia data release, Gaia DR2, consisting of astrometry, photometry, radial velocities, and information on astrophysical parameters and variability, for sources brighter than magnitude 21. In addition epoch astrometry and photometry are provided for a modest sample of minor planets in the solar system. Aims. A summary of the contents of Gaia DR2 is presented, accompanied by a discussion on the differences with respect to Gaia DR1 and an overview of the main limitations which are still present in the survey. Recommendations are made on the responsible use of Gaia DR2 results. Methods. The raw data collected with the Gaia instruments during the first 22 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into this second data release, which represents a major advance with respect to Gaia DR1 in terms of completeness, performance, and richness of the data products. Results. Gaia DR2 contains celestial positions and the apparent brightness in G for approximately 1.7 billion sources. For 1.3 billion of those sources, parallaxes and proper motions are in addition available. The sample of sources for which variability information is provided is expanded to 0 : 5 million stars. This data release contains four new elements: broad-band colour information in the form of the apparent brightness in the G(BP) (330-680 nm) and G(RP) (630-1050 nm) bands is available for 1.4 billion sources; median radial velocities for some 7 million sources are presented; for between 77 and 161 million sources estimates are provided of the stellar effective temperature, extinction, reddening, and radius and luminosity; and for a pre-selected list of 14 000 minor planets in the solar system epoch astrometry and photometry are presented. Finally, Gaia DR2 also represents a new materialisation of the celestial reference frame in the optical, the Gaia-CRF2, which is the first optical reference frame based solely on extragalactic sources. There are notable changes in the photometric system and the catalogue source list with respect to Gaia DR1, and we stress the need to consider the two data releases as independent. Conclusions. Gaia DR2 represents a major achievement for the Gaia mission, delivering on the long standing promise to provide parallaxes and proper motions for over 1 billion stars, and representing a first step in the availability of complementary radial velocity and source astrophysical information for a sample of stars in the Gaia survey which covers a very substantial fraction of the volume of our galaxy.

  • 47.
    Brunner, M.
    et al.
    Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
    Danilovich, T.
    Chalmers Univ Technol, Onsala Space Observ, Dept Space Earth & Environm, S-43992 Onsala, Sweden;Katholieke Univ Leuven, Dept Phys & Astron, Inst Astron, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
    Ramstedt, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Marti-Vidal, I.
    Chalmers Univ Technol, Onsala Space Observ, Dept Space Earth & Environm, S-43992 Onsala, Sweden.
    De Beck, E.
    Chalmers Univ Technol, Onsala Space Observ, Dept Space Earth & Environm, S-43992 Onsala, Sweden.
    Vlemmings, W. H. T.
    Chalmers Univ Technol, Onsala Space Observ, Dept Space Earth & Environm, S-43992 Onsala, Sweden.
    Lindqvist, M.
    Chalmers Univ Technol, Onsala Space Observ, Dept Space Earth & Environm, S-43992 Onsala, Sweden.
    Kerschbaum, F.
    Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna, Austria.
    Molecular line study of the S-type AGB star W Aquilae ALMA observations of CS, SiS, SiO and HCN2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 617, article id A23Article in journal (Refereed)
    Abstract [en]

    Context: With the outstanding spatial resolution and sensitivity of the Atacama Large Millimeter/sub-millimeter Array (ALMA), molecular gas other than the abundant CO can be observed and resolved in circumstellar envelopes (CSEs) around evolved stars, such as the binary S-type asymptotic giant branch (AGB) star W Aquilae.

    Aims: We aim to constrain the chemical composition of the CSE and determine the radial abundance distribution, the photospheric peak abundance, and isotopic ratios of a selection of chemically important molecular species in the innermost CSE of W Aql. The derived parameters are put into the context of the chemical evolution of AGB stars and are compared with theoretical models.

    Methods: We employ one-dimensional radiative transfer modeling - with the accelerated lambda iteration (ALI) radiative transfer code-of the radial abundance distribution of a total of five molecular species (CS, SiS, (SiS)-Si-30, (SiO)-Si-29 and (HCN)-C-13) and determine the best fitting model parameters based on high-resolution ALMA observations as well as archival single-dish observations. The additional advantage of the spatially resolved ALMA observations is that we can directly constrain the radial profile of the observed line transitions from the observations.

    Results: We derive abundances and e-folding radii for CS, SiS, (SiS)-Si-30, (SiO)-Si-29 and (HCN)-C-13 and compare them to previous studies, which are based only on unresolved single-dish spectra. Our results are in line with previous results and are more accurate due to resolution of the emission regions.

  • 48.
    Bujarrabal, V.
    et al.
    Observ Astron Nacl OAN IGN, Apartado 112, Alcala De Henares 28803, Spain.
    Alcolea, J.
    Observ Astron Nacl OAN IGN, C Alfonso 12 3, Madrid 28014, Spain.
    Mikolajewska, J.
    Polish Acad Sci, Nicolaus Copernicus Astron Ctr, Ul Bartycka 18, PL-00716 Warsaw, Poland.
    Castro-Carrizo, A.
    Inst Radioastron Millimetr, 300 Rue Piscine, F-38406 St Martin Dheres, France.
    Ramstedt, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    High-resolution observations of the symbiotic system R Aqr Direct imaging of the gravitational effects of the secondary on the stellar wind2018In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 616, article id L3Article in journal (Refereed)
    Abstract [en]

    We have observed the symbiotic stellar system R Aqr, aiming to describe the gravitational interaction between the white dwarf (WD) and the wind from the Mira star, the key phenomenon driving the symbiotic activity and the formation of nebulae in such systems. We present high-resolution ALMA maps of the (CO)-C-12 and (CO)-C-13 J = 3-2 lines, the 0.9 mm continuum distribution, and some high-excitation molecular lines in R Aqr. The maps, which have resolutions ranging between 40 mas and less than 20 mas probe the circumstellar regions at suborbital scales as the distance between the stars is similar to 40 mas. Our observations show the gravitational effects of the secondary on the stellar wind. The AGB star was identified in our maps from the continuum and molecular line data, and we estimated the probable position of the secondary from a new estimation of the orbital parameters. The (preliminary) comparison of our maps with theoretical predictions is surprisingly satisfactory and the main expected gravitational effects are directly mapped for the first time. We find a strong focusing in the equatorial plane of the resulting wind, which shows two plumes in opposite directions that have different velocities and very probably correspond to the expected double spiral due to the interaction. Our continuum maps show the very inner regions of the nascent bipolar jets, at scales of some AU. Continuum maps obtained with the highest resolution show the presence of a clump that very probably corresponds to the emission of the ionized surroundings of the WD and of a bridge of material joining both stars, which is likely material flowing from the AGB primary to the accretion disk around the WD secondary.

  • 49. Caffau, E.
    et al.
    Ludwig, H. -G.
    Steffen, M.
    Ayres, T. R.
    Bonifacio, P.
    Cayrel, R.
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Plez, B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    The photospheric solar oxygen project - I. Abundance analysis of atomic lines and influence of atmospheric models2008In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 488, no 3, p. 1031-1046Article in journal (Refereed)
    Abstract [en]

    Context. The solar oxygen abundance has undergone a major downward revision in the past decade, the most noticeable one being the update including 3D hydrodynamical simulations to model the solar photosphere. Up to now, such an analysis has only been carried out by one group using one radiation-hydrodynamics code. Aims. We investigate the photospheric oxygen abundance considering lines from atomic transitions. We also consider the relationship between the solar model used and the resulting solar oxygen abundance, to understand whether the downward abundance revision is specifically related to 3D hydrodynamical effects. Methods. We performed a new determination of the solar photospheric oxygen abundance by analysing different high-resolution high signal-to-noise ratio atlases of the solar flux and disc-centre intensity, making use of the latest generation of CO5BOLD 3D solar model atmospheres. Results. We find 8.73 <= log (N-O/N-H) + 12 <= 8.79. The lower and upper values represent extreme assumptions on the role of collisional excitation and ionisation by neutral hydrogen for the NLTE level populations of neutral oxygen. The error of our analysis is +/- (0.04 +/- 0.03) dex, the last being related to NLTE corrections, the first error to any other effect. The 3D "granulation effects" do not play a decisive role in lowering the oxygen abundance. Conclusions. Our recommended value is log (N-O/N-H) = 8.76 +/- 0.07, considering our present ignorance of the role of collisions with hydrogen atoms on the NLTE level populations of oxygen. The reasons for lower O abundances in the past are identified as (1) the lower equivalent widths adopted and (2) the choice of neglecting collisions with hydrogen atoms in the statistical equilibrium calculations for oxygen.

  • 50.
    Calvo, F.
    et al.
    Ist Ric Solari Locarno IRSOL, Via Patocchi 57 Prato Pernice, CH-6605 Locarno, Switzerland.;Univ Geneva, Observ Geneva, Ch Maillettes 51, CH-1290 Sauverny, Switzerland..
    Steiner, O.
    Ist Ric Solari Locarno IRSOL, Via Patocchi 57 Prato Pernice, CH-6605 Locarno, Switzerland.;Kiepenheuer Inst Sonnenphys, Schoneckstr 6, D-79104 Freiburg, Germany..
    Freytag, Bernd
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Theoretical Astrophysics.
    Non-magnetic photospheric bright points in 3D simulations of the solar atmosphere2016In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 596, article id A43Article in journal (Refereed)
    Abstract [en]

    Context. Small-scale bright features in the photosphere of the Sun, such as faculae or G-band bright points, appear in connection with small-scale magnetic flux concentrations. Aims. Here we report on a new class of photospheric bright points that are free of magnetic fields. So far, these are visible in numerical simulations only. We explore conditions required for their observational detection. Methods. Numerical radiation (magneto-) hydrodynamic simulations of the near-surface layers of the Sun were carried out. The magnetic field-free simulations show tiny bright points, reminiscent of magnetic bright points, only smaller. A simple toy model for these non-magnetic bright points (nMBPs) was established that serves as a base for the development of an algorithm for their automatic detection. Basic physical properties of 357 detected nMBPs were extracted and statistically evaluated. We produced synthetic intensity maps that mimic observations with various solar telescopes to obtain hints on their detectability. Results. The nMBPs of the simulations show a mean bolometric intensity contrast with respect to their intergranular surroundings of approximately 20%, a size of 60-80 km, and the isosurface of optical depth unity is at their location depressed by 80-100 km. They are caused by swirling downdrafts that provide, by means of the centripetal force, the necessary pressure gradient for the formation of a funnel of reduced mass density that reaches from the subsurface layers into the photosphere. Similar, frequently occurring funnels that do not reach into the photosphere, do not produce bright points. Conclusions. Non-magnetic bright points are the observable manifestation of vertically extending vortices (vortex tubes) in the photosphere. The resolving power of 4-m-class telescopes, such as the DKIST, is needed for an unambiguous detection of them.

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