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Umbriel

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MOON

Umbriel

The dark, ancient, heavily cratered Uranian moon with the enigmatic Wunda crater.

Orbits Uranus
  • Darkest of Uranus's five major moons u2014 albedo just 21%.
  • Features the 131 km Wunda crater whose floor shines unusually bright.

Physical Properties

585 km
1.275e21 kg
1.39 g/cm³
0.252 m/s²
99.46 h
0.21
75 K

Orbit

Uranus
266,000 km
0.0039
0.128°
4.144 d

Sources & Further Reading

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.

Umbriel is the third-largest moon of Uranus and has the darkest, most ancient surface of the five major Uranian moons. Its low albedo points to a coating of dark organic-rich material. Umbriel’s signature feature is Wunda, a 131 km crater whose remarkably bright floor has never been satisfactorily explained.