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Credit: NASA/ESA/M. Brown (Caltech) Public domain — NASA Media Usage Guidelines
Physical Properties
1,163 km
1.6466e22 kg
2.43 g/cm³
0.824 m/s²
1.39 km/s
387 h
0.96
30 K
Orbit
Sun
67.86 AU
0.43607
44°
38.27 AU
97.46 AU
559 yr
Notable Moons
Sources & Further Reading
- NASA — official mission / factsheet page
- Wikipedia — extensive cross-referenced article
- NASA u2014 Eris
- JPL SBDB u2014 136199 Eris
Numerical values (radius, mass, orbital elements, temperatures) are drawn from NASA NSSDC Planetary Fact Sheets, JPL Horizons, and the JPL Small-Body Database. Last refreshed: 2026-04-18 18:19:25.
Eris is the most-massive dwarf planet in the Solar System — roughly 27% more massive than Pluto, though slightly smaller in diameter. Its discovery in 2005 directly prompted the IAU’s 2006 reclassification: if Eris were to be called a planet, many other large KBOs would have to be too, so a new category of “dwarf planet” was created. Eris orbits the Sun in the scattered disc, ranging from 38 to 97 AU. It has one known moon, Dysnomia.