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Encyclopedia > Uranus > Satellites > Umbriel

UMBRIEL : SATELLITE II OF URANUS



Credit : C. J. Hamilton/NASA

Umbriel (Uranus II) was discovered by William Lassell in 1851. Its revolution period is 4 days et 4 hours. 

Origin of the name : click here.

Characteristics Values
Semi-major axis in km  265 998 
Revolution period   4.144 days 
Rotation period  4.144 days
Orbital velocity 5 km/s
Inclination on Uranus' equator 0.13°
Eccentricity of the orbit 0.004
Equatorial diameter (Earth=1)  0.09
Equatorial diameter 1169 km
Visual magnitude at the opposition 14.8
Flattening  0 
Mass (Uranus=1)  1.35/100 000 
Density (Water=1)  1.4 
Escape velocity 538 m/s
Reflectivity (geometric albedo ) 0.18
The highest peak   ? 
Deepest pit 6000m
Atmosphere no
Composition ice  
silicates