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On the observational bias of the Trojan swarms
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
2010 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 516, A22- p.Article in journal (Refereed) Published
Abstract [en]

Aims. I investigate whether the Trojan swarms are observationally biased and place a completion limit on their absolute magnitude. Methods. Observations including Trojans from a number of observation sites are cross-checked with orbital integration of known Trojans and a set of fictitious Trojan orbits. Results. The completion limit for the Trojans swarms can be set to be H = 11.5 mag. The L-5 swarm is 71% of the L-4 size down to this limit. It is not likely that any existing set of orbital elements can have escaped detections. However, parts of the orbital element space, especially in the inclination, are biased for Trojans fainter than the completion limit. In the absolute magnitude interval 11.5-13 mag, 65% of new objects should have inclinations 15-40 degrees, while this inclination interval currently contains 49% of Trojans in the complete interval 9.5-11.5 mag. Trojans fainter than an absolute magnitude of 13 mag are also clearly biased in the ascending node at values coinciding with the Milky Way.

Place, publisher, year, edition, pages
2010. Vol. 516, A22- p.
Keyword [en]
minor planets, asteroids: general, planets and satellites: individual: Jupiter
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-147278DOI: 10.1051/0004-6361/200912629ISI: 000280275400037OAI: oai:DiVA.org:uu-147278DiVA: diva2:400113
Available from: 2011-02-24 Created: 2011-02-24 Last updated: 2012-10-11Bibliographically approved
In thesis
1. A Study of Jupiter Trojans
Open this publication in new window or tab >>A Study of Jupiter Trojans
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Jupiter Trojan asteroid dynamics have been studied for a long time but it is only within the last decades that the known population has become large enough to make other studies meaningful. In four articles I have been scratching the surface of the unknown Trojan knowledge space.

Paper I presents photometric observations confirming a larger variety in surface redness for the smaller Trojans compared to the larger ones, in line with the groups in the outer main asteroid belt. However, the largest Trojans are significantly redder compared to the largest Cybele and Hilda asteroids.

Paper II is an investigation of the Trojan discovery completeness. The analysis shows that all Trojans down to a limiting absolute magnitude of H=11.5 mag have been discovered. Missing Trojans in the almost discovery-completed section should have inclinations above the mean of the same group. The faintest Trojans are discovery biased due to orbit orientations similar to the Milky Way.

Paper III is a general review of dynamical and physical properties of the discovery-completed sample of Jupiter Trojans found in Paper II. The two Trojan swarms are often treated as being equal, but are different in a number of details. Two known facts are that the L5 swarm is less rich, while the L4 swarm has a larger fraction of low inclination Trojans. Trojans are in general red objects but the mean redness is higher for Trojans which have not collided compared to Trojans in families.

Paper IIII is an investigation of Trojan collisions, family detection and evolution. Collision circumstances were mapped using numerical simulations and recorded Trojan close approaches. Synthetic families were created and evolved numerically. The result suggests that the HCM family detection technique can find Trojan families even in a densely populated parameter space. However, interlopers cannot be avoided at any level but their contribution should be less than 30%. Synthetic families can be identified with backwards orbital integrations for times up to a Gyr-scale. However, there are discrepancies between real Trojan families and my synthetic families.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 207 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 918
Jupiter Trojans, Trojan asteroids, Minor planets, Solar system
National Category
Astronomy, Astrophysics and Cosmology
urn:nbn:se:uu:diva-172151 (URN)978-91-554-8334-0 (ISBN)
Public defence
2012-05-24, Siegbahnsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:00 (English)
Available from: 2012-04-27 Created: 2012-04-02 Last updated: 2012-10-18Bibliographically approved

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