Dwarf planet Xena officially named Eris

The icy body that sparked a debate over what makes a planet, and ultimately led to Pluto's demotion to "dwarf planet," will be named Eris.

The icy body that sparked a debate over what makes a planet, and ultimately led to Pluto's demotion to "dwarf planet," will be named Eris.

The dwarf planet was nicknamed Xena by its discoverer, Michael Brown of the California Institute of Technology and given the designation 2003 UB313 by the International Astronomy Union.

The group announced Wednesday that the body will be named Eris, after the Greek goddess of discord, and its satellite will be named Dysnomia, after the deity's daughter.

Because the dwarf planet took its nickname from the nameof TV's warrior princess, the moon was for a time informally known as Gabrielle, after Xena's sidekick.

Eris and Dysnomia are the most distant known objects in the solar system, almost 100 times further away from the sunthan Earth. Eris is the largest known dwarf planet, only slightly larger than Pluto.

The discovery of Eris prompted astronomers to decide on a definition for "planet." If Eris had been included, it may have increased the number of planets in the solar system to as many as 15.

In the end, the International Astronomy Union decided on a definition that excluded Eris and, bynecessity, Pluto, demoting the former ninth planet to dwarf planet status.

Like all small bodies in the solar system, such asdwarf planets and asteroids, Eris and Dysnomia were each given a sequential number, as was Pluto, which is now officially designated 134340 Pluto.