Key facts
- Mean diameter
- 2,326 km
- Mass
- 1.66 × 10^22 kg (0.00278 Earths)
- Surface gravity
- 0.82 m/s² (0.0836 g)
- Escape velocity
- 1.38 km/s
- Mean temperature
- -231 °C
- Rotation period
- 378.9 hours
- Orbital period
- 203,830 days
- Mean distance from the Sun
- 10,125 million km
- Sunlight travel time
- 9 h 22 min
- Confirmed moons
- 1
Atmosphere
None detected while far from the Sun; methane frost covers the surface.
Composition and structure
Rock and ice, slightly more massive than Pluto.
Discovery and exploration
Discovered in 2005 by Mike Brown, Chad Trujillo and David Rabinowitz; its discovery led the IAU to define 'dwarf planet' in 2006.