Pluto may not be a planet anymore, but it still has a few moons. The International Astronomical Union (IAU) is announcing that the names Kerberos and Styx have officially been recognised for the fourth and fifth moons of Pluto, which were discovered in 2011 and 2012.
Both the names come from Greek mythology. Kerberos (or Cerberus) was the three headed dog, or hellhound, which guards the gates of the Underworld. Styx was the river which separated the world from the underworld. Cerberus stood guard by its shore and saw that no one who crossed the Styx was able to leave the underworld - or join it, for whatever reason.
The new moons were discovered recently by the NASA/ESA Hubble Space Telescope Wide Field Camera 3, and the names were given by public votes in a recently held contest.
The IAU acts as the arbiter of the naming process of celestial bodies, and is advised and supported by astronomers active in different fields.