The Second Earth Trojan 2020 XL5

The Earth Trojans are coorbitals librating around the Lagrange points L 4 or L 5 of the Sun–Earth system. Although many numerical studies suggest that they can maintain their dynamical status and be stable on timescales up to a few tens of thousands of years or even longer, they remain an elusive po...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2021-12, Vol.922 (2)
Main Authors: Hui, Man-To, Wiegert, Paul A., Tholen, David J., Föhring, Dora
Format: Article
Language:English
Subjects:
Asteroids
Earth
Eccentric orbits
Lagrangian equilibrium points
Near-Earth objects
Trojan asteroids
Venus
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Summary:The Earth Trojans are coorbitals librating around the Lagrange points L 4 or L 5 of the Sun–Earth system. Although many numerical studies suggest that they can maintain their dynamical status and be stable on timescales up to a few tens of thousands of years or even longer, they remain an elusive population. Thus far only one transient member (2010 TK7) has been discovered serendipitously. Here, we present a dynamical study of asteroid 2020 XL5. With our meticulous follow-up astrometric observations of the object, we confirmed that it is a new Earth Trojan. However, its eccentric orbit brings it close encounters with Venus on a frequent basis. Based on our N-body integration, we found that the asteroid was captured into the current Earth Trojan status in the fifteenth century, and then it has a likelihood of 99.5% to leave the L 4 region within the next ∼10 kyr. Therefore, it is most likely that 2020 XL5 is dynamically unstable over this timescale.
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/ac37bf