Pluto

Pluto, formal designation 134340 Pluto, is a dwarf planet in the Sol system, and the second-largest known dwarf planet (after Eris) as well as the tenth-largest body observed directly orbiting Sol. It was named after the Roman God of the Underworld. The Remote Scanning Outpost Democritus is situated in orbit over this dwarf planet. On November 3, 2552, the monitoring station detected Cortana's signal in Slipspace with Dr. Halsey's message to Lord Hood.

As of 2552 there are no human facilities on the dwarf-planet's surface, however several military and scientific stations orbit Pluto. The only known such facility is Kelvin Research Station.

History
Pluto was discovered in 1930, and was considered to be the ninth and final planet of the Solar System. Its largest moon, Charon, was discovered in 1978. In 2005, two smaller moons were discovered. During 2006, arguments began to arise on whether Pluto was actually large enough to be considered a planet. After much debate, Pluto (along with the asteroid Ceres and the object Eris) became newly classified as a dwarf planet.

In 2006, a space probe named New Horizons was launched to gather more information on Pluto. It arrived at the dwarf planet in 2015 and was the first spacecraft to ever visit Pluto.

List of appearances

 * Halo: Ghosts of Onyx
 * ''Halo Evolutions
 * The Impossible Life and the Possible Death of Preston J. Cole
 * Halo: Hunters in the Dark
 * Halo 5: Guardians