A Pluto--Charon Concerto II. Formation of a Circumbinary Disk of Debris After the Giant Impact

TL;DR

This study uses numerical simulations to explore the evolution of debris from the Pluto-Charon giant impact, revealing the formation of an extended circumbinary disk with implications for satellite formation.

Contribution

It provides new insights into the long-term dynamical evolution of debris post-impact and the resulting disk structure around Pluto-Charon.

Findings

Most debris is ejected within 1000 years.

A circumbinary disk forms within the orbital plane.

Disks are more extended than narrow rings from TNO impacts.

Abstract

Using a suite of numerical calculations, we consider the long-term evolution of circumbinary debris from the Pluto-Charon giant impact. Initially, these solids have large eccentricity and pericenters near Charon's orbit. On time scales of 100-1000 yr, dynamical interactions with Pluto and Charon lead to the ejection of most solids from the system. As the dynamics moves particles away from the barycenter, collisional damping reduces the orbital eccentricity of many particles. These solids populate a circumbinary disk in the Pluto-Charon orbital plane; a large fraction of this material lies within a `satellite zone' that encompasses the orbits of Styx, Nix, Kerberos, and Hydra. Compared to the narrow rings generated from the debris of a collision between a trans-Neptunian object (TNO) and Charon, disks produced after the giant impact are much more extended and may be a less promising option for producing small circumbinary satellites.