The smallest known moon of Pluto, a highly elongated body orbiting just beyond Charon.
Styx is the smallest of Pluto’s five known moons. It was discovered in 2012 with the Hubble Space Telescope during observations that helped assess the Pluto system before New Horizons arrived. Its orbit lies just beyond Charon and inside the orbit of Nix.
New Horizons resolved Styx as a highly elongated body. Studies of the Pluto system’s dynamics suggest that its rotation may be complex rather than simply tidally locked.
Even though New Horizons could resolve only limited surface detail on Styx, its orbit and shape help scientists study how Pluto’s compact satellite system formed and evolved. The leading idea is that the moons formed from debris produced by an ancient collision involving Pluto and another Kuiper Belt object.
NASA’s Eyes on the Solar System places Pluto in its wider solar system setting and lets you examine the Pluto–Charon system in three dimensions. Rotate the view, zoom in or out, and use the time controls to follow the modeled motion of the system.
NASA Eyes is an interactive visualization provided by NASA/JPL and loads from eyes.nasa.gov. If the embedded view is unavailable, use the full-screen link above.
Pluto has five known moons. Charon is by far the largest and forms a closely coupled pair with Pluto. Farther out, the four much smaller moons—Styx, Nix, Kerberos and Hydra—follow nearly circular orbits around the Pluto–Charon system.
Diagram is schematic; sizes and orbital distances are not to scale.
NASA Science provides mission background, observations and image collections; Wikipedia offers a broader reference overview with citations.
