Oberon (moon)

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This article is about the Uranus moon. For other uses, see Oberon.
Oberon   

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Discovery
Discovered by: William Herschel
Discovery date: January 11, 1787
Orbital characteristics
Semi-major axis: 583,520 km
Mean radius of orbit: 583,519 km
Eccentricity: 0.0014
Orbital period: 13.463234 d
Inclination: 0.058° (to Uranus' equator)
Satellite of: Uranus
Physical characteristics
Mean radius: 761.4 km (0.1194 Earths)
Surface area: 7,285,000 km²
Volume: 1,849,000,000 km³
Mass: 3.014×1021 kg (5.0455×10-4 Earths)
Mean density: 1.63 g/cm³
Equatorial surface gravity: 0.346 m/s2
Escape velocity: 0.73 km/s
Rotation period: presumed synchronous[1]
Albedo: 0.23
Temperature: ~61 K

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. He reported it and Titania the same year.[2][3] He would later report four more satellites, which would turn out to be spurious.[4]

Contents

[edit] 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. The adjectival form of the name is Oberonian.

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

It is also designated Uranus IV.

[edit] 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.

[edit] Trivia

This article contains a trivia section.
Content in this section should be integrated into other appropriate areas of the article or removed, and the trivia section removed.

[edit] Notes

  1. ^ An application of a rough formula indicates tidal locking on a timescale of the order of 300,000 years (see Tidal locking).
  2. ^ An Account of the Discovery of Two Satellites Revolving Round the Georgian Planet, Philosophical Transactions of the Royal Society of London, Vol. 77, pp. 125-129, (1787)
  3. ^ On George's Planet and its satellites, Philosophical Transactions of the Royal Society of London, Vol. 78, pp. 364-378, (1788)
  4. ^ On the Discovery of Four Additional Satellites of the Georgium Sidus; The Retrograde Motion of Its Old Satellites Announced; And the Cause of Their Disappearance at Certain Distances from the Planet Explained, Philosophical Transactions of the Royal Society of London, Vol. 88, pp. 47-79, (1798)

[edit] See also


v • d • e
Natural satellites of the Solar System
Planetary satellites Terrestrial · Martian · Jovian · Saturnian · Uranian · Neptunian
Other satellite systems Plutonian · Eridian · Asteroid satellites
Largest satellites Ganymede · Titan · Callisto · Io · Moon · Europa · Triton
Titania · Rhea · Oberon · Iapetus · Charon · Umbriel · Ariel · Dione · Tethys  · Enceladus · Miranda · Proteus · Mimas
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