The celestial object, whose discovery prompted astronomers to demote Pluto from the ranks of planets, has been renamed "Eris" (previously, "Xena"):
Having caused so much consternation in the International Astronomical Union (IAU), the object has been called Eris, after the Greek goddess of discord.
Eris is larger than Pluto, which put scientists in the fix of having to call them both planets - or neither. Both bodies have now been put in the new classification of "dwarf planets".
Eris' discoverer, Michael Brown of the California Institute of Technology, told the Associated Press that the name was an obvious choice, calling it "too perfect to resist".