Oberon (moon)

Encyclopedia : O : OB : OBE : Oberon (moon)

Oberon

Click image for description
Discovery
Discovered by William Herschel
Discovered in January 11, 1787
Orbital characteristics
Semi-major axis 583,520 km
Mean radius 583,519 km
Eccentricity 0.0014
Orbital period 13.463234 d
Inclination 0.058° (to Uranus' equator)
Is a satellite of Uranus
Physical characteristics
Mean diameter 1522.8 km (0.1194 Earths)
Surface area 7,285,000 km²
Volume 1,849,000,000 km³
Mass kg (5.0455 Earths)>
Mean density 1.63 g/cm³
Surface gravity 0.346 m/s²
Escape velocity 0.73 km/s
Rotation period presumably synchronousAn application of a rough formula (see the tidal locking article) indicates tidal locking on a timescale of the order of 300,000 years.
Axial tilt ?°
Albedo 0.23
Surface temp.
min mean max
? K ~61 K ? K

Atmospheric pressure 0 kPa
Oberon (oe'-bər-on, IPA /ˈɔʊbərɒn/) is the outermost of the major moons of the planet Uranus. It was discovered on January 11, 1787 by William Herschel.

Contents

1 Name
2 Physical features
3 Notes
4 See also

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 ([link]). 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 Faries 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.

Although its interior make-up is uncertain, one model suggests that 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.

Oberon (moon)

Name

Physical features

Notes

See also