Dwarf planet
Eris
A Pluto-sized world on a steep, 557-year orbit.
Eris takes about 557 years to orbit the Sun on a stretched orbit tilted about 44 degrees to the planets. At its farthest it swings out to nearly 98 AU. It spins once every 25.9 hours, a day close to Earth's.
How it moves
- Eris orbits the Sun about once every 557.6 years.
- Its orbit is highly eccentric (0.438), ranging from about 38 to 98 AU from the Sun.
- The orbit is inclined about 44 degrees, far out of the plane of the planets.
- Eris rotates once every 25.9 hours.
- Its moon Dysnomia circles it on a nearly circular orbit lasting about 16 days.
Facts
- Mean radius
- 1,200 km
- Mass
- 1.660e+22 kg
- Surface gravity
- 0.77 m/s²
- Rotation period
- 25.9 hours
- Orbital period
- 203,649 days
- Average distance from the Sun
- 67.934 AU
- Eccentricity
- 0.4382
- Known moons
- 1
- Discovered
- 2005, by Mike Brown, Chad Trujillo, and David Rabinowitz (in Palomar images taken October 21, 2003)
The discovery of Eris helped prompt the IAU's 2006 decision that created the dwarf planet category.
Sources: ssd.jpl.nasa.gov, ssd-api.jpl.nasa.gov, science.nasa.gov