Generation of Highly Inclined Trans-Neptunian Objects by Planet Nine

TL;DR

This paper demonstrates that a distant, eccentric, and mildly inclined Planet Nine can explain the origins of highly inclined and retrograde trans-Neptunian objects, revealing a new dynamical pathway for their formation.

Contribution

It introduces a new dynamical mechanism driven by Planet Nine that accounts for highly inclined trans-Neptunian objects, including retrograde ones, within the solar system's evolution.

Findings

Planet Nine's parameters explain inclined TNOs.

Highly inclined TNOs originate from the scattered disk.

Dynamical pathway links Drac and Niku to the extended scattered disk.

Abstract

The trans-Neptunian region of the solar system exhibits an intricate dynamical structure, much of which can be explained by an instability-driven orbital history of the giant planets. However, the origins of a highly inclined, and in certain cases retrograde, population of trans-Neptunian objects remain elusive within the framework of this evolutionary picture. In this work, we show that the existence of a distant, Neptune-like planet that resides on an eccentric and mildly inclined orbit fully accounts for the anomalous component the trans-Neptunian orbital distribution. Adopting the same parameters for Planet Nine as those previously invoked to explain the clustering of distant Kuiper belt orbits in physical space, we carry out a series of numerical experiments which elucidate the physical process though which highly inclined Kuiper belt objects with semi-major axes smaller than 100 AU are generated. The identified dynamical pathway demonstrates that enigmatic members of the Kuiper belt such as Drac and Niku are derived from the extended scattered disk of the solar system.