(provisional designation ) is a resonant trans-Neptunian object discovered on 18 December 2001, by American astronomers Chad Trujillo and Michael Brown at the Palomar Observatory in California. It measures approximately 345 kilometers in diameter.
is locked in 3:5 mean-motion resonance with Neptune. When it makes three revolutions around the Sun, Neptune makes exactly five. The rotation period of is estimated to be .
In 2010, thermal flux from in the far-infrared was measured by the Herschel Space Telescope. As a result, its size has been estimated to be .