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Solar System Exploration
Umbriel: Facts & Figures
   Back to Uranus   Overview   Gallery   Facts & Figures   News 
Discovered By
W. Lassell
Date of Discovery
Orbit Size Around Uranus (semi-major axis)
Metric: 266,000 km
English: 165,285 miles
Periapsis (closest)
Metric: 264,963 km
Apoapsis (farthest)
Metric: 267,037 km
Sidereal Orbit Period (Length of Year)
0.011345654 Earth years
4.144 Earth days
Orbit Circumference
Metric: 1,671,320.94 km
Average Orbit Velocity
Metric: 16,804.6 km/h
Orbit Eccentricity
Orbit Inclination
0.128 degree
Mean Radius
Metric: 584.7 km
Equatorial Circumference
Metric: 3,673.8 km
Metric: 837,313,109 km3
Metric: 1,221,414,772,974,210,000,000 kg
Scientific Notation: 1.2214 x 1021 kg
Metric: 1.459 g/cm3
Surface Area
Metric: 4,296,116.52 km2
Surface Gravity
Metric: 0.238 m/s2
Escape Velocity
Metric: 1,901 km/h
Rotation Period (Length of Day)
By Comparison: Synchronous with Uranus

Additional Information:

-USGS Astrogeology: Gazetteer of Planetary Nomenclature:

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Last Updated: 12 Aug 2013