Styx is a small moon of Pluto. It was discovered in June 2012 by Mark Robert Showalter using the Hubble Space Telescope, and was announced a month later. The New Horizons spacecraft photographed the moon in July 2015.
The moon is the second closest moon to Pluto, and was the fifth discovered. It is the smallest known moon of Pluto. It is approximately 16 km (9.9 miles) at its longest dimension. It has an orbital period of 20.1 days.[1]
History[]
Discovery[]
Styx was discovered by a team led by Mark Robert Showalter, using fourteen sets of images taken by the Hubble Space Telescope. It was announced on July 11, 2012.
Name[]
Styx was at first given the name S/2012 (134340) 1, because it was the first satellite "(S)" discovered orbiting Pluto, which has the minor planet designation 134340.
The moon was named after "Styx", a mythological river that separates the world of the living from the realm of the dead. Some names that were proposed were Cerebeus, Romulus, and Vulcan.
Physical characteristics[]
New Horizons discovered that Styx has a very irregularly shape, and measures around 16 km x 9 km x 8 km (9.9 mi x 5.6 mi x 5.0 mi). Its thought that Styx formed from debris lofted by a collision, and is expected to have created a body consisting mainly of water ice.[2]
Orbit[]
Styx orbits Pluto 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. It has an orbital period of around 20.16155 days. Like most of the other Pluto moons, Styx is not tidally locked, and its rotation varies over short timescales.