small moon · moon of the dwarf planet Pluto
Styx
The smallest known moon of Pluto, found by Hubble in 2012 – a body only about ten kilometres across, circling between Charon and Nix.
- Distance from Earth today
- 5.35 billion km35.77 AU · light: 4 h 57 min
- Distance from the Sun today
- 5.33 billion km35.64 AU
- As of
- 4 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
- Diameter
- 10.4 km
- Mean distance from the planet
- 43,200 km
- Orbital period
- 20.2 days
- Orbital eccentricity
- 0.025
- Orbital inclination
- 0.0°
Source of the figures: JPL SSD – Planetary Satellites (public domain).
Discovery: 2012 – Mark R. Showalter et al. (Hubble Space Telescope)
Description
Styx is the smallest and the most recently discovered of Pluto's five moons. Mark Showalter's team found it in 2012 in Hubble Space Telescope images taken to look for rings or debris that could endanger New Horizons. It orbits closest to the Pluto–Charon pair of the four small moons, about 43,000 km from Pluto, once every 20 days. During the 2015 flyby New Horizons could see it only from far away, as a small, elongated speck. Like Kerberos, it was named in 2013; Styx is the goddess of the river that, in Greek myth, separates the world of the living from the underworld.