Orbit determination of the moons of the Pluto-Charon system

TL;DR

This paper investigates the complex orbital dynamics of Pluto's small moons, revealing that observed variations are likely caused by forced oscillations from the central binary system rather than measurement errors.

Contribution

It introduces a new understanding of moon orbit variations as forced oscillations due to the binary nature of Pluto-Charon, challenging previous assumptions based on Keplerian models.

Findings

Orbital variations may result from forced oscillations, not eccentricities.

Numerical and analytical methods support the intrinsic origin of observed orbital differences.

Central binary potential significantly influences moon orbit behavior.

Abstract

Four small moons (Styx, Nix, Kerberos and Hydra) are at present known to orbit around the barycenter of Pluto and Charon, which are themselves considered a binary dwarf-planet due to their relatively high mass ratio. The central, non-axisymmetric potential induces moon orbits inconvenient to be described by Keplerian osculating elements. Here, we report that observed orbital variations, may not be the result of orbital eccentricities or observational uncertainties, but may be due to forced oscillations caused by the central binary. We show, using numerical integration and analytical considerations, that the differences reported on their orbital elements, may well arise from this intrinsic behavior rather than limitations on our instruments.