A Pluto-Charon Sonata: The Dynamical Architecture of the Circumbinary Satellite System

TL;DR

This study uses extensive n-body simulations to investigate the stability and potential discovery of new satellites in the Pluto-Charon system, highlighting the likelihood of stable orbits beyond the outermost moon Hydra and proposing observational strategies.

Contribution

It provides the first detailed dynamical analysis of the Pluto-Charon satellite system's stability zones and suggests observational methods to detect small, distant moons.

Findings

Small moons within 1.1 a_H are ejected within 10 Myr.

Orbits beyond 1.1 a_H are stable over 100 Myr.

JWST and ground-based telescopes can detect 1-2 km satellites outside Hydra.

Abstract

Using a large suite of n-body simulations, we explore the discovery space for new satellites in the Pluto-Charon system. For the adopted masses and orbits of the known satellites, there are few stable prograde or polar orbits with semimajor axes $a \lesssim 1.1~a_H$, where $a_H$ is the semimajor axis of the outermost moon Hydra. Small moons with radii $r \lesssim$ 2 km and $a \lesssim 1.1~a_H$ are ejected on time scales ranging from several yr to more than 10 Myr. Orbits with $a \gtrsim 1.1~a_H$ are stable on time scales exceeding 100 Myr. Near-IR and mid-IR imaging with JWST and ground-based occultation campaigns with 2-3-m class telescopes can detect 1-2 km satellites outside the orbit of Hydra. Searches for these moons enable new constraints on the masses of the known satellites and on theories for circumbinary satellite formation.