Stability of Neptune's distant resonances in the presence of Planet Nine

TL;DR

This study examines the stability of Neptune's distant resonances and the influence of a hypothetical Planet Nine on Trans-Neptunian Objects, revealing how such objects are affected by planetary perturbations and potential resonances.

Contribution

It provides new insights into the dynamical evolution of TNOs in Neptune's resonances and the impact of Planet Nine on their orbital stability and distribution.

Findings

Objects beyond 12:1 resonance are efficiently removed by Planet Nine.

Some TNOs may be in Neptune's n:1 resonances, including candidates like 2014 JW80 and 2014 OS394.

Resonant interactions with Neptune and Planet Nine influence TNOs' orbital evolution.

Abstract

Trans-Neptunian Objects (TNOs) in the scattered disk with 50 < a < 100 au are thought to cluster near Neptune's n:1 resonances (e.g: 3:1, 4:1, and so on). While these objects spend lengthy periods of time at large heliocentric distances, if their perihelia remain less than around 40 au, their dynamical evolution is still largely coupled to Neptune's. Conversely, around a dozen extreme TNOs with a > 250 au and detached perihelia seem to exist in a regime where they are too distant to be affected by the giant planets, and too close for their dynamics to be governed by external forces. Recent work suggests that the apparent alignment of these orbits in physical space is a signature of gravitational shepherding by a distant massive planet. In this paper, we investigate the evolution of TNOs in each of Neptune's n:1 resonances between the 3:1 and 14:1. We conclude that both resonant and non-resonant objects beyond the 12:1 near ~157 au are removed rather efficiently via perturbations from the hypothetical Planet Nine. Additionally, we uncover a population of simulated TNOs with a < 100 au, 40 < q < 45 au and low inclinations that experience episodes of resonant interactions with both Neptune and Planet Nine. Finally, we simulate the evolution of observed objects with a > 100 au and identify several TNOs that are potentially locked in n:1 resonances with Neptune; including the most distant known resonant candidates 2014 JW80 and 2014 OS394 that appear to be in the 10:1 and 11:1 resonances, respectively. Our results suggest that the detection of similar remote objects might provide a useful constraint on hypotheses invoking the existence of additional distant planets.