The Moon Orbits Around the Binary System of Pluto and Charon

The Moon Orbits Around the Binary System of Pluto and Charon

Pluto and Charon form a binary system. Around their barycenter, four recently discovered moons are orbiting: Styx, Nix, Kerberos and Hydra. In this work, two separate approaches were utilized to model their orbits. At first, all bodies were simulated using an n-body integrator and then outcomes were validated by a theoretical model. The motions that the four small moons follow are a superposition of forced oscillations by the binary system and mutual gravitational interactions. Results indicated that we cannot use Keplerian elements to describe the circumbinary orbits, as the central potential by the dwarf binary planet forces the small moons into several oscillations. Even when demanding a zero-orbital eccentricity, distances appeared to have many fluctuations through time. Lastly, we noticed that the mutual effects induce many long period perturbations, especially for the lighter moons, whereas the binary effects mainly dominate in the high frequency region.