paper

On the Dynamical Origins of Retrograde Jupiter Trojans and their Connection to High-Inclination TNOs

arXiv:2008.11242 · doi:10.1007/s10569-020-09985-1

Abstract

Over the course of the last decade, observations of highly-inclined (orbital inclination i > 60°) Trans-Neptunian Objects (TNOs) have posed an important challenge to current models of solar system formation (Levison et al. 2008; Nesvorný 2015). These remarkable minor planets necessitate the presence of a distant reservoir of strongly-out-of-plane TNOs, which itself requires some dynamical production mechanism (Gladman et al. 2009; Gomes et al. 2015; Batygin and Brown 2016). A notable recent addition to the census of high-i minor bodies in the solar system is the retrograde asteroid 514107 Ka'epaoka'awela, which currently occupies a 1:-1 mean motion resonance with Jupiter at i = 163° (Wiegert et al. 2017). In this work, we delineate a direct connection between retrograde Jupiter Trojans and high-i Centaurs. First, we back-propagate a large sample of clones of Ka'epaoka'awela for 100 Ma numerically, and demonstrate that long-term stable clones tend to decrease their inclination steadily until it concentrates between 90° and 135°, while their eccentricity and semi-major axis increase, placing many of them firmly into the trans-Neptunian domain. Importantly, the clones show significant overlap with the synthetic high-i Centaurs generated in Planet 9 studies (Batygin et al. 2019), and hint at the existence of a relatively prominent, steady-state population of minor bodies occupying polar trans-Saturnian orbits. Second, through direct numerical forward-modeling, we delineate the dynamical pathway through which conventional members of the Kuiper Belt's scattered disk population can become retrograde Jovian Trojan resonators in presence of Planet 9.

arXiv commentAccepted to Celestial Mechanics and Dynamical Astronomy's Topical Collection on Trans-Neptunian Objects (11 pages, 4 figures, 1 table)

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