On the Estimation of Circumbinary Orbital Properties

TL;DR

This paper introduces a rapid, approximate technique to analyze satellite orbits around binary systems, helping distinguish free eccentricity from binary-driven oscillations, with applications to planetary formation and satellite growth.

Contribution

The paper presents a novel, efficient method for characterizing circumbinary orbits and demonstrates its effectiveness on real systems and simulations, aiding understanding of planetary and satellite formation.

Findings

Method accurately distinguishes free eccentricity from binary-driven oscillations.

Application to simulations shows dynamical cooling promotes satellite mergers.

Results support formation scenarios for circumbinary planets and moons.

Abstract

We describe a fast, approximate method to characterize the orbits of satellites around a central binary in numerical simulations. A goal is to distinguish the free eccentricity -- random motion of a satellite relative to a dynamically cool orbit -- from oscillatory modes driven by the central binary's time-varying gravitational potential. We assess the performance of the method using the Kepler-16, Kepler-47, and Pluto-Charon systems. We then apply the method to a simulation of orbital damping in a circumbinary environment, resolving relative speeds between small bodies that are slow enough to promote mergers and growth. These results illustrate how dynamical cooling can set the stage for the formation of Tatooine-like planets around stellar binaries and the small moons around the Pluto-Charon binary planet.