Search for L5 Earth Trojans with DECam
Abstract
Most of the major planets in the Solar system support populations of coorbiting bodies, known as Trojans, at their L4 and L5 Lagrange points. In contrast, Earth has only one known coorbiting companion. This paper presents the results from a search for Earth Trojans (ETs) using the DECam instrument on the Blanco Telescope at CTIO. This search found no additional Trojans in spite of greater coverage compared to previous surveys of the L5 point. Therefore, the main result of this work is to place the most stringent constraints to date on the population of ETs. These constraints depend on assumptions regarding the underlying population properties, especially the slope of the magnitude distribution (which in turn depends on the size and albedo distributions of the objects). For standard assumptions, we calculate upper limits to a 90 per cent confidence limit on the L5 population of N_{ET} < 1 for magnitude H < 15.5, N_{ET} = 6085 for H < 19.7, and N_{ET} = 97 for H = 20.4. This latter magnitude limit corresponds to Trojans ∼300 m in size for albedo 0.15. At H = 19.7, these upper limits are consistent with previous L4 ET constraints and significantly improve L5 constraints.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 March 2020
 DOI:
 10.1093/mnras/staa232
 arXiv:
 arXiv:2001.08229
 Bibcode:
 2020MNRAS.492.6105M
 Keywords:

 methods: observational;
 minor planets;
 asteroids: general;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 17 pages, 12 figures, Accepted to MNRAS