Oberon

Click image for description
Discovery
Discovered by	W. Herschel
Discovered in	January 11, 1787
Orbital characteristics
Mean radius	583519 km
Eccentricity	~0.0016
Orbital period	13.463234d
Inclination	~0.7°
Is a satellite of	Uranus
Physical characteristics
Mean diameter	1522.8 km
Surface area	km2
Mass	3.014×1021 kg
Mean density	1.63 g/cm3
Surface gravity	0.346 m/s2
Rotation period	?
Axial tilt	?°
Albedo	0.24
Surface temp.	min mean max  ? K  ? K  ? K
Atmospheric pressure	0 kPa

Oberon (oh'-bur-on) is the outermost of the major moons of the planet Uranus. It was discovered on 1787-01-11 by William Herschel.

Name

The name "Oberon" and the names of all four satellites of Uranus then known were suggested by Herschel's son John Herschel in 1852 at the request of William Lassell, who had discovered Ariel and Umbriel the year before ([1]). Lassell had earlier endorsed Herschel's 1847 naming scheme for the seven then-known satellites of Saturn and had named his newly-discovered eighth satellite Hyperion in accordance with Herschel's naming scheme in 1848.

All of the moons of Uranus are named for characters from Shakespeare or Alexander Pope. Oberon was named after Oberon, the king of the Faeries in A Midsummer Night's Dream.

It is also designated Uranus IV.

Physical features

So far the only close-up images of Oberon are from the Voyager 2 probe, which photographed the moon during its Uranus flyby in January, 1986. At the time of the flyby the southern hemisphere of the moon was pointed towards the Sun so only it was studied.

Oberon is composed of roughly 50% water ice, 30% silicate rock, and 20% methane-related carbon/nitrogen compounds. It has an old, heavily cratered, and icy surface which shows little evidence of internal activity other than some unknown dark material that apparently covers the floors of many craters.

Scientists recognise only two types of geological feature on Oberon: craters and chasmata.

See also

• List of geological features on Oberon