Evaluating the Dynamical Stability of Outer Solar System Objects in the Presence of Planet Nine

Abstract

We evaluate the dynamical stability of a selection of outer solar system objects in the presence of the proposed new Solar System member Planet Nine. We use a Monte Carlo suite of numerical N-body integrations to construct a variety of orbital elements of the new planet and evaluate the dynamical stability of eight Trans-Neptunian objects (TNOs) in the presence of Planet Nine. These simulations show that some combinations of orbital elements ($a,e$) result in Planet Nine acting as a stabilizing influence on the TNOs, which can otherwise be destabilized by interactions with Neptune. These simulations also suggest that some TNOs transition between several different mean-motion resonances during their lifetimes while still retaining approximate apsidal anti-alignment with Planet Nine. This behavior suggests that remaining in one particular orbit is not a requirement for orbital stability. As one product of our simulations, we present an {\it a posteriori} probability distribution for the semi-major axis and eccentricity of the proposed Planet Nine based on TNO stability. This result thus provides additional evidence that supports the existence of this proposed planet. We also predict that TNOs can be grouped into multiple populations of objects that interact with Planet Nine in different ways: one population may contain objects like Sedna and 2012 VP${}_{113}$, which do not migrate significantly in semi-major axis in the presence of Planet Nine and tend to stay in the same resonance; another population may contain objects like 2007 TG${}_{422}$ and 2013 RF${}_{98}$, which may both migrate and transition between different resonances.

accepted to AJ

References in corpus (8)

• Cross Sections for Planetary Systems Interacting with Passing Stars and Binaries
• Discovery of A New Retrograde Trans-Neptunian Object: Hint of A Common Orbital Plane for Low Semi-Major Axis, High Inclination TNOs and Centaurs
• Solar Obliquity Induced by Planet Nine
• The inclination of the planetary system relative to the solar equator may be explained by the presence of Planet 9
• Constraints on Planet Nine's Orbit and Sky Position within a Framework of Mean Motion Resonances
• Solar Obliquity Induced by Planet Nine: Simple Calculation
• Exploring the Outer Solar System with the ESSENCE Supernova Survey
• The Pan-STARRS 1 Discoveries of five new Neptune Trojans

Cited by in corpus (6)

• The Planet Nine Hypothesis
• Dynamical Evolution Induced by Planet Nine
• OSSOS XV: Probing the Distant Solar System with Observed Scattering TNOs
• Circularizing Planet Nine through dynamical friction with an extended, cold planetesimal belt
• Stellar winds as a mechanism to tilt the spin axes of Sun-like stars
• The Case for a Large-Scale Occultation Network