Styx is a small natural satellite of Pluto. Styx orbits the Pluto–Charon barycenter at a distance of 42,656 km, putting it between the orbits of Charon and Nix. It is in an 11:6 orbital resonance with Hydra, and an 11:9 resonance with Nix (the ratios represent numbers of orbits completed per unit time; the period ratios are the inverses). As a result of this "Laplace-like" 3-body resonance, it has conjunctions with Nix and Hydra in a 2:5 ratio. In contrast to its orbit, Styx's rotation is very chaotic; like the other small Plutonian moons, Styx's rotation is not tidally locked, and it varies rapidly over short timescales (with a current rate of about 3.239 days).

Styx (moon) - Wikipedia, the free encyclopedia