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Montez, R. J., Ramstedt, S., Kastner, J. H., Vlemmings, W. & Sanchez, E. (2017). A Catalog of GALEX Ultraviolet Emission from Asymptotic Giant Branch Stars. Astrophysical Journal, 841(1), Article ID 33.
Open this publication in new window or tab >>A Catalog of GALEX Ultraviolet Emission from Asymptotic Giant Branch Stars
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2017 (English)In: Astrophysical Journal, ISSN 0004-637X, E-ISSN 1538-4357, Vol. 841, no 1, 33Article in journal (Refereed) Published
Abstract [en]

We have performed a comprehensive study of the UV emission detected from asymptotic giant branch (AGB) stars by the Galaxy Evolution Explorer (GALEX). Of the 468 AGB stars in our sample, 316 were observed by GALEX. In the near-UV (NUV) bandpass (lambda(eff) similar to 2310 angstrom), 179 AGB stars were detected and 137 were not detected. Only 38 AGB stars were detected in the far-UV (FUV) bandpass (lambda(eff) similar to 1528 angstrom). We find that NUV emission is correlated with optical to near-infrared emission, leading to higher detection fractions among the brightest, and hence closest, AGB stars. Comparing the AGB time-variable visible phased light curves to corresponding GALEX NUV phased light curves, we find evidence that for some AGB stars the NUV emission varies in phase with the visible light curves. We also find evidence that the NUV emission and possibly the FUV emission are anticorrelated with the circumstellar envelope density. These results suggest that the origin of the GALEX-detected UV emission is an inherent characteristic of the AGB stars that can most likely be traced to a combination of photospheric and chromospheric emission. In most cases, UV detections of AGB stars are not likely to be indicative of the presence of binary companions.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2017
Keyword
general, stars: AGB and post-AGB, stars: chromospheres, ultraviolet: stars
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-326239 (URN)10.3847/1538-4357/aa704d (DOI)000402310500019 ()
Funder
EU, European Research Council, 614264
Available from: 2017-07-06 Created: 2017-07-06 Last updated: 2017-07-06Bibliographically approved
Wittkowski, M., Hofmann, K.-H. -., Höfner, S., Le Bouquin, J. B., Nowotny, W., Paladini, C., . . . Weigelt, G. (2017). Aperture synthesis imaging of the carbon AGB star R Sculptoris Detection of a complex structure and a dominating spot on the stellar disk. Astronomy and Astrophysics, 601, Article ID A3.
Open this publication in new window or tab >>Aperture synthesis imaging of the carbon AGB star R Sculptoris Detection of a complex structure and a dominating spot on the stellar disk
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2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 601, A3Article in journal (Refereed) Published
Abstract [en]

Aims. We present near-infrared interferometry of the carbon-rich asymptotic giant branch (AGB) star R Sculptoris (R Scl). Methods. We employ medium spectral resolution K-band interferometry obtained with the instrument AMBER at the Very Large Telescope Interferometer (VLTI) and H-band low spectral resolution interferometric imaging observations obtained with the VLTI instrument PIONIER. We compare our data to a recent grid of dynamic atmosphere and wind models. We compare derived fundamental parameters to stellar evolution models. Results. The visibility data indicate a broadly circular resolved stellar disk with a complex substructure. The observed AMBER squared visibility values show drops at the positions of CO and CN bands, indicating that these lines form in extended layers above the photosphere. The AMBER visibility values are best fit by a model without a wind. The PIONIER data are consistent with the same model. We obtain a Rosseland angular diameter of 8.9 +/- 0.3 mas, corresponding to a Rosseland radius of 355 +/- 55 R-Theta, an effective temperature of 2640 +/- 80 K, and a luminosity of log L/L-Theta = 3.74 +/- 0.18. These parameters match evolutionary tracks of initial mass 1.5 +/- 0.5 M-Theta and current mass 1.3 +/- 0.7 M-Theta. The reconstructed PIONIER images exhibit a complex structure within the stellar disk including a dominant bright spot located at the western part of the stellar disk. The spot has an H- band peak intensity of 40% to 60% above the average intensity of the limb-darkening-corrected stellar disk. The contrast between the minimum and maximum intensity on the stellar disk is about 1:2.5. Conclusions. Our observations are broadly consistent with predictions by dynamic atmosphere and wind models, although models with wind appear to have a circumstellar envelope that is too extended compared to our observations. The detected complex structure within the stellar disk is most likely caused by giant convection cells, resulting in large-scale shock fronts, and their effects on clumpy molecule and dust formation seen against the photosphere at distances of 2-3 stellar radii.

Place, publisher, year, edition, pages
EDP Sciences, 2017
Keyword
techniques: interferometric, stars: AGB and post-AGB, stars: atmospheres, stars: fundamental parameters, stars: mass-loss, stars: individual: R Scl
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-327053 (URN)10.1051/0004-6361/201630214 (DOI)000402313500003 ()
Available from: 2017-08-03 Created: 2017-08-03 Last updated: 2017-08-03Bibliographically approved
De Nutte, R., Decin, L., Olofsson, H., Lombaert, R., de Koter, A., Karakas, A., . . . Van de Sande, M. (2017). Nucleosynthesis in AGB stars traced by oxygen isotopic ratios I. Determining the stellar initial mass by means of the O-17/O-18 ratio. Astronomy and Astrophysics, 600, Article ID A71.
Open this publication in new window or tab >>Nucleosynthesis in AGB stars traced by oxygen isotopic ratios I. Determining the stellar initial mass by means of the O-17/O-18 ratio
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2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 600, A71Article in journal (Refereed) Published
Abstract [en]

Aims. We seek to investigate the O-17/O-18 ratio for a sample of AGB stars containing M-, S-, and C-type stars. These ratios are evaluated in relation to fundamental stellar evolution parameters: the stellar initial mass and pulsation period.

Methods. Circumstellar (CO)-C-13-O-16, (CO)-C-12-O-17, and (CO)-C-12-O-18 line observations were obtained for a sample of nine stars with various single-dish long-wavelength facilities. Line intensity ratios are shown to relate directly to the surface O-17/O-18 abundance ratio.

Results. Stellar evolution models predict the O-17/O-18 ratio to be a sensitive function of initial mass and to remain constant throughout the entire TP-AGB phase for stars initially less massive than 5 M-circle dot. This makes the measured ratio a probe of the initial stellar mass.

Conclusions. Observed O-17/O-18 ratios are found to be well in the range predicted by stellar evolution models that do not consider convective overshooting. From this, accurate initial mass estimates are calculated for seven sources. For the remaining two sources, there are two mass solutions, although there is a larger probability that the low-mass solution is correct. Finally, we present hints at a possible separation between M/S- and C-type stars when comparing the O-17/O-18 ratio to the stellar pulsation period.

Place, publisher, year, edition, pages
EDP SCIENCES S A, 2017
Keyword
stars: AGB and post-AGB, stars: evolution, stars: fundamental parameters, circumstellar matter
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-324337 (URN)10.1051/0004-6361/201629195 (DOI)000400754000041 ()
Funder
EU, FP7, Seventh Framework ProgrammeEU, European Research Council, 646758 AEROSOLSwedish Research Council
Available from: 2017-06-15 Created: 2017-06-15 Last updated: 2017-06-15Bibliographically approved
Kerschbaum, F., Maercker, M., Brunner, M., Lindqvist, M., Olofsson, H., Mecina, M., . . . Wittkowski, M. (2017). Rings and filaments: The remarkable detached CO shell of U Antliae. Astronomy and Astrophysics, 605, Article ID A116.
Open this publication in new window or tab >>Rings and filaments: The remarkable detached CO shell of U Antliae
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2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 605, A116Article in journal (Refereed) Published
Abstract [en]

Aims. Our goal is to characterize the intermediate age, detached shell carbon star U Antliae morphologically and physically in order to study the mass-loss evolution after a possible thermal pulse.

Methods. High spatial resolution ALMA observations of unprecedented quality in thermal CO lines allow us to derive first critical spatial and temporal scales and constrain modeling efforts to estimate mass-loss rates for both the present day as well as the ejection period of the detached shell.

Results. The detached shell is remarkably thin, overall spherically symmetric, and shows a barely resolved filamentary substructure possibly caused by instabilities in the interaction zone of winds with different outflow velocities. The expansion age of the detached shell is of the order of 2700 yr and its overall width indicates a high expansion-velocity and high mass-loss period of only a few hundred years at an average mass-loss rate of approximate to 10(-5) M-circle dot yr(-1). The post-high-mass-loss-rate-epoch evolution of U Ant shows a significant decline to a substantially lower gas expansion velocity and a mass-loss rate amounting to 4 x 10(-8) M-circle dot yr(-1), at present being consistent with evolutionary changes as predicted for the period between thermal pulses.

Keyword
stars: AGB and post-AGB, stars: carbon, stars: evolution, stars: mass-loss
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-337756 (URN)10.1051/0004-6361/201730665 (DOI)000412231200087 ()
Funder
Swedish Research Council
Note

Acknowledgements: F.K. and M.B. acknowledge funding by the Austrian Science Fund FWF under project number P23586. M.B. further acknowledges funding through the uni: docs fellowship of the University of Vienna. M.M., H.O., and W.V. acknowledge financial support from the Swedish Research Council. C.P. is supported by the Belgian Fund for Scientific Research F.R.S.-FNRS.

Available from: 2018-01-12 Created: 2018-01-12 Last updated: 2018-01-12Bibliographically approved
De Beck, E., Decin, L., Ramstedt, S., Olofsson, H., Menten, K. M., Patel, N. A. & Vlemmings, W. H. (2017). Search for aluminium monoxide in the winds of oxygen-rich AGB stars. Astronomy and Astrophysics, 598, Article ID A53.
Open this publication in new window or tab >>Search for aluminium monoxide in the winds of oxygen-rich AGB stars
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2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 598, A53Article in journal (Refereed) Published
Abstract [en]

Context. Aluminium monoxide (AlO) is likely efficiently depleted from the gas around oxygen-rich evolved stars to form alumina (Al2O3) clusters and dust seeds. The presence of AlO gas in the extended atmospheres of evolved stars has been derived from optical spectroscopy. More recently, AlO gas was also detected at long wavelengths around the supergiant VY CMa and the oxygenrich asymptotic giant branch star o Cet (Mira A). The central role aluminium might play in dust formation and wind driving, in combination with these first detections of AlO at long wavelengths, shows the need for a wider search for this molecule in the winds of evolved stars. Aims. The detection at long wavelengths of emission in rotational transitions of AlO towards asymptotic giant branch stars can help constrain the presence and location of AlO gas in the outflows and ultimately also the efficiency of the depletion process. Methods. In search of AlO, we mined data obtained with APEX, the IRAM 30m telescope, Herschel / HIFI, SMA, and ALMA, which were primarily aimed at studying other species around asymptotic giant branch stars. We report here on observations of AlO towards a sample of eight oxygen-rich asymptotic giant branch stars in different rotational transitions, up to seven for some stars. Results. We present definite detections of one rotational transition of AlO for o Cet and R Aqr, and tentative detections of one transition for R Dor and o Cet and two transitions for IK Tau and W Hya. The presented spectra of WX Psc, R Cas, and TX Cam show no signature of AlO. For o Cet, R Aqr, and IK Tau, we find that the AlO (N = 9 8) emission likely traces the inner parts of the wind, out to only a few tens of AU, where the gas has not yet been accelerated to its terminal velocity. This is in agreement with recently published results from a detailed study on o Cet. Conclusions. The conclusive detections of AlO emission in the case of o Cet and R Aqr confirm the presence of AlO in the gas phase in outflows of asymptotic giant branch stars. The tentative detections further support this. Since most of the observations presented in this study were obtained with stronger emission from other species than AlO in mind, observations with higher sensitivity in combination with high angular resolution will improve our understanding of the presence and behaviour of AlO. From the current data sets we cannot firmly conclude whether there is a direct correlation between the wind properties and the detection rate of AlO emission. We hope that this study can serve as a stimulus to perform sample studies in search of AlO in oxygen-rich outflows.

Place, publisher, year, edition, pages
EDP SCIENCES S A, 2017
Keyword
stars: AGB and post-AGB, stars: mass-loss, circumstellar matter, astrochemistry, submillimeter: stars
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-320501 (URN)10.1051/0004-6361/201628928 (DOI)000394465000053 ()
Funder
EU, European Research Council, 614264 646758 AEROSOLSwedish Research Council
Available from: 2017-04-20 Created: 2017-04-20 Last updated: 2017-04-20Bibliographically approved
Ramstedt, S., Mohamed, S., Vlemmings, W. H., Danilovich, T., Brunner, M., De Beck, E., . . . Quintana-Lacaci, G. (2017). The circumstellar envelope around the S-type AGB star W Aql Effects of an eccentric binary orbit. Astronomy and Astrophysics, 605, Article ID A126.
Open this publication in new window or tab >>The circumstellar envelope around the S-type AGB star W Aql Effects of an eccentric binary orbit
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2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 605, A126Article in journal (Refereed) Published
Abstract [en]

Context. Recent observations at subarcsecond resolution, now possible also at submillimeter wavelengths, have shown intricate circumstellar structures around asymptotic giant branch (AGB) stars, mostly attributed to binary interaction. The results presented here are part of a larger project aimed at investigating the effects of a binary companion on the morphology of circumstellar envelopes (CSEs) of AGB stars.

Aims. AGB stars are characterized by intense stellar winds that build CSEs around the stars. Here, the CO(J = 3 -> 2) emission from the CSE of the binary S-type AGB star W Aql has been observed at subarcsecond resolution using ALMA. The aim of this paper is to investigate the wind properties of the AGB star and to analyse how the known companion has shaped the CSE.

Methods. The average mass-loss rate during the creation of the detected CSE is estimated through modelling, using the ALMA brightness distribution and previously published single-dish measurements as observational constraints. The ALMA observations are presented and compared to the results from a 3D smoothed particle hydrodynamics (SPH) binary interaction model with the same properties as the W Aql system and with two different orbital eccentricities. Three-dimensional radiative transfer modelling is performed and the response of the interferometer is modelled and discussed.

Results. The estimated average mass-loss rate of W Aql is (M) over dot = 3.0 x 10(-6) M-circle dot yr(-1) and agrees with previous results based on single-dish CO line emission observations. The size of the emitting region is consistent with photodissociation models. The inner 10 0 0 of the CSE is asymmetric with arc-like structures at separations of 23" scattered across the denser sections. Further out, weaker spiral structures at greater separations are found, but this is at the limit of the sensitivity and field of view of the ALMA observations.

Conclusions. The CO(J = 3 -> 2) emission is dominated by a smooth component overlayed with two weak arc patterns with different separations. The larger pattern is predicted by the binary interaction model with separations of similar to 10" and therefore likely due to the known companion. It is consistent with a binary orbit with low eccentricity. The smaller separation pattern is asymmetric and coincides with the dust distribution, but the separation timescale (200 yr) is not consistent with any known process of the system. The separation of the known companions of the system is large enough to not have a very strong effect on the circumstellar morphology. The density contrast across the envelope of a binary with an even larger separation will not be easily detectable, even with ALMA, unless the orbit is strongly asymmetric or the AGB star has a much larger mass-loss rate.

Keyword
stars: AGB and post-AGB, circumstellar matter, binaries: general, submillimeter: stars
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-337758 (URN)10.1051/0004-6361/201730934 (DOI)000412231200088 ()
Funder
EU, European Research Council, 614264; 646758EU, FP7, Seventh Framework Programme, 610256 (NANOCOSMOS)
Available from: 2018-01-12 Created: 2018-01-12 Last updated: 2018-01-12Bibliographically approved
Doan, L., Ramstedt, S., Vlemmings, W. H., Höfner, S., De Beck, E., Kerschbaum, F., . . . Wittkowski, M. (2017). The extended molecular envelope of the asymptotic giant branchstar π1 Gruis as seen by ALMA: I. Large-scale kinematic structure and CO excitation properties. Astronomy and Astrophysics, 605, Article ID A28.
Open this publication in new window or tab >>The extended molecular envelope of the asymptotic giant branchstar π1 Gruis as seen by ALMA: I. Large-scale kinematic structure and CO excitation properties
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2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 605, A28Article in journal (Refereed) Published
Abstract [en]

Context. The S-type asymptotic giant branch (AGB) star pi(1) Gru has a known companion at a separation of 2 ''.7 (approximate to 400 AU). Previous observations of the circumstellar envelope (CSE) show strong deviations from spherical symmetry. The envelope structure, including an equatorial torus and a fast bipolar outflow, is rarely seen in the AGB phase and is particularly unexpected in such a wide binary system. Therefore a second, closer companion has been suggested, but the evidence is not conclusive.

Aims. The aim is to make a 3D model of the CSE and to constrain the density and temperature distribution using new spatially resolved observations of the CO rotational lines.

Methods. We have observed the J = 3-2 line emission from (CO)-C-12 and (CO)-C-13 using the compact arrays of the Atacama Large Millimeter/submillimeter Array (ALMA). The new ALMA data, together with previously published (CO)-C-12 J = 2-1 data from the Submillimeter Array (SMA), and the (CO)-C-12 J = 5-4 and J = 9-8 lines observed with Herschel/Heterodyne Instrument for the Far-Infrared (HIFI), is modeled with the 3D non-LTE radiative transfer code SHAPEMOL.

Results. The data analysis clearly confirms the torus-bipolar structure. The 3D model of the CSE that satisfactorily reproduces the data consists of three kinematic components: a radially expanding torus with velocity slowly increasing from 8 to 13 km s(-1) along the equator plane; a radially expanding component at the center with a constant velocity of 14 km s(-1); and a fast, bipolar outflow with velocity proportionally increasing from 14 km s(-1) at the base up to 100 km s(-1) at the tip, following a linear radial dependence. The results are used to estimate an average mass-loss rate during the creation of the torus of 7.7 x 10(-7) M-circle dot yr(-1). The total mass and linear momentum of the fast outflow are estimated at 7.3 x 10(-4) M-circle dot and 9.6 x 10(37) g cm s(-1), respectively. The momentum of the outflow is in excess (by a factor of about 20) of what could be generated by radiation pressure alone, in agreement with recent findings for more evolved sources. The best-fit model also suggests a (CO)-C-12/(CO)-C-13 abundance ratio of 50. Possible shaping scenarios for the gas envelope are discussed.

Keyword
stars: AGB and post-AGB; stars: mass-loss; stars: individual: pi(1) Gru; stars: general; radio lines: stars; binaries: general
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-327430 (URN)10.1051/0004-6361/201730703 (DOI)000412231200057 ()
Funder
EU, European Research Council, 614264
Available from: 2017-08-11 Created: 2017-08-11 Last updated: 2018-01-12Bibliographically approved
Maercker, M., Vlemmings, W. H., Brunner, M., De Beck, E., Humphreys, E. M., Kerschbaum, F., . . . Ramstedt, S. (2016). A detailed view of the gas shell around R Sculptoris with ALMA. Astronomy and Astrophysics, 586, Article ID A5.
Open this publication in new window or tab >>A detailed view of the gas shell around R Sculptoris with ALMA
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2016 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 586, A5Article in journal (Refereed) Published
Abstract [en]

Context. During the asymptotic giant branch (AGB) phase, stars undergo thermal pulses - short-lived phases of explosive helium burning in a shell around the stellar core. Thermal pulses lead to the formation and mixing-up of new elements to the stellar surface. They are hence fundamental to the chemical evolution of the star and its circumstellar envelope. A further consequence of thermal pulses is the formation of detached shells of gas and dust around the star, several of which have been observed around carbon-rich AGB stars. Aims. We aim to determine the physical properties of the detached gas shell around R Sculptoris, in particular the shell mass and temperature, and to constrain the evolution of the mass-loss rate during and after a thermal pulse. Methods. We analyse (CO)-C-12(1-0), (CO)-C-12(2-1), and (CO)-C-12(3-2) emission, observed with the Atacama Large Millimeter/submillimeter Array (ALMA) during Cycle 0 and complemented by single-dish observations. The spatial resolution of the ALMA data allows us to separate the detached shell emission from the extended emission inside the shell. We perform radiative transfer modelling of both components to determine the shell properties and the post-pulse mass-loss properties. Results. The ALMA data show a gas shell with a radius of 19.'' 5 expanding at 14.3 km s(-1). The different scales probed by the ALMA Cycle 0 array show that the shell must be entirely filled with gas, contrary to the idea of a detached shell. The comparison to single-dish spectra and radiative transfer modelling confirms this. We derive a shell mass of 4.5 x 10(-3) M-circle dot with a temperature of 50 K. Typical timescales for thermal pulses imply a pulse mass-loss rate of 2.3 x 10(-5) M-circle dot yr(-1). For the post-pulse mass-loss rate, we find evidence for a gradual decline of the mass-loss rate, with an average value of 1.6 x 10(-5) M-circle dot yr(-1). The total amount of mass lost since the last thermal pulse is 0.03 M-circle dot, a factor four higher compared to classical models, with a sharp decline in mass-loss rate immediately after the pulse. Conclusions. We find that the mass-loss rate after a thermal pulse has to decline more slowly than generally expected from models of thermal pulses. This may cause the star to lose significantly more mass during a thermal pulse cycle, which affects the lifetime on the AGB and the chemical evolution of the star, its circumstellar envelope, and the interstellar medium.

Keyword
stars: AGB and post-AGB, binaries: general, stars: carbon, stars: evolution, stars: mass-loss
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-281832 (URN)10.1051/0004-6361/201527128 (DOI)000369715900016 ()
Funder
EU, FP7, Seventh Framework Programme, 623898.11EU, European Research Council, 614264Swedish Research Council
Available from: 2016-04-06 Created: 2016-03-30 Last updated: 2017-11-30Bibliographically approved
Khouri, T., Vlemmings, W. H., Ramstedt, S., Lombaert, R., Maercker, M. & De Beck, E. (2016). ALMA observations of the vibrationally excited rotational CO transition v=1, J=3-2 towards five AGB stars. Monthly notices of the Royal Astronomical Society, 463(1), L74-L78.
Open this publication in new window or tab >>ALMA observations of the vibrationally excited rotational CO transition v=1, J=3-2 towards five AGB stars
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2016 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 463, no 1, L74-L78 p.Article in journal (Refereed) Published
Abstract [en]

We report the serendipitous detection with the Atacama Large Millimeter/submillimeter Array (ALMA) of the vibrationally excited pure-rotational CO transition, J = 3 - 2 towards five asymptotic giant branch (AGB) stars, Cet, R Aqr, R Scl, W Aql, and pi(1) Gru. The observed lines are formed in the poorly understood region located between the stellar surface and the region where the wind starts, the so-called warm molecular layer. We successfully reproduce the observed lines profiles using a simple model. We constrain the extents, densities, and kinematics of the region where the lines are produced. R Aqr and R Scl show inverse P-Cygni line profiles which indicate infall of material on to the stars. The line profiles of Cet and R Scl show variability. The serendipitous detection towards these five sources shows that vibrationally excited rotational lines can be observed towards a large number of nearby AGB stars using ALMA. This opens a new possibility for the study of the innermost regions of AGB circumstellar envelopes.

Keyword
line: profiles, stars: AGB and post-AGB, circumstellar matter
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-312081 (URN)10.1093/mnrasl/slw161 (DOI)000386157100016 ()
Available from: 2017-02-03 Created: 2017-01-04 Last updated: 2017-11-29Bibliographically approved
Olofsson, H., Vlemmings, W., Maercker, M., Humphreys, E., Lindqvist, M., Nyman, L. & Ramstedt, S. (2016). An ALMA view of the post-AGB object HD101584. In: Kwok, S Leung, KC (Ed.), 11th Pacific Rim Conference On Stellar Astrophysics: Physics And Chemistry Of The Late Stages Of Stellar Evolution, Pts 1-6. Paper presented at 11th Pacific Rim Conference on Stellar Astrophysics - Physics and Chemistry of the Late Stages of Stellar Evolution, DEC 14-15, 2015, Univ Hong Kong, Hong Kong, PEOPLES R CHINA. IOP PUBLISHING LTD, Article ID UNSP 042005.
Open this publication in new window or tab >>An ALMA view of the post-AGB object HD101584
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2016 (English)In: 11th Pacific Rim Conference On Stellar Astrophysics: Physics And Chemistry Of The Late Stages Of Stellar Evolution, Pts 1-6 / [ed] Kwok, S Leung, KC, IOP PUBLISHING LTD , 2016, UNSP 042005Conference paper, Published paper (Refereed)
Abstract [en]

ALMA cycles 1 and 3 observations of CO isotopologues and 1.3mm continuum are used in a study of the circumstellar environment of the binary HD 101584, a post-AGB star and a low-mass companion that is most likely a post-common-envelope-evolution system. These data are supplemented with new information from OH maser emission. It is inferred that the large- scale circumstellar medium has a bipolar hour-glass structure, seen almost pole-on, formed by an energetic, >= 150 km s(-1), jet. Significant amount of material still resides in the central region. It is proposed that the circumstellar morphology is related to an event which took place <= 500 yr ago, possibly a capture event where the companion spiralled in towards the AGB star. Several observed features remain to be explained, and may hint to a more complicated scenario.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2016
Series
Journal of Physics Conference Series, ISSN 1742-6588 ; 728
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-321274 (URN)10.1088/1742-6596/728/4/042005 (DOI)000397958000030 ()
Conference
11th Pacific Rim Conference on Stellar Astrophysics - Physics and Chemistry of the Late Stages of Stellar Evolution, DEC 14-15, 2015, Univ Hong Kong, Hong Kong, PEOPLES R CHINA
Available from: 2017-05-02 Created: 2017-05-02 Last updated: 2017-05-02Bibliographically approved
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