major moon · moon of Uranus
Oberon
The outermost large moon of Uranus, an ancient, heavily cratered world named after the fairy king in Shakespeare.
- Distance from Earth today
- 2.77 billion km18.52 AU · light: 2 h 34 min
- Distance from the Sun today
- 2.91 billion km19.43 AU
- As of
- 3 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
- Diameter
- 1,523 km
- Mass
- 3,076 × 10¹⁸ kg
- Density
- 1,664 kg/m³
- Mean distance from the planet
- 583,511 km
- Orbital period
- 13.5 days
- Orbital eccentricity
- 0.0020
- Orbital inclination
- 0.1°
Source of the figures: JPL SSD – Planetary Satellites (public domain).
Discovery: 1787 – William Herschel
Description
Oberon is the second-largest and outermost of Uranus's major moons, discovered by William Herschel in 1787 and named after the king of the fairies in A Midsummer Night's Dream. Its old, icy surface is saturated with impact craters, some of which have dark material on their floors, and Voyager 2 spotted at least one very tall mountain rising above its edge. Oberon spends part of each orbit outside Uranus's magnetosphere, exposed directly to the solar wind. Voyager 2 imaged it from a distance in 1986.