Dwarf planet Eris. Computer artwork of dwarf planet Eris, which was formerly known as 2003 UB313, and nicknamed Xena until it was officially named. Above Eris is its satellite Dysnomia. The Sun is at upper left. Images taken by the Hubble Space Telescope have shown that Eris is slightly larger than Pluto. Until the vote by the International Astronomical Union (IAU) on 24 August 2006 to modify the definition of a planet, it had been referred to as the 10th planet. It is now classified as a dwarf planet, an object large enough to be spherical due to gravity, that is in orbit around the sun, has not cleared its neigbourhood and is not a satellite of another planet. It is an icy body located in the Kuiper Belt of the outer solar system.