Oberon (moon)

Oberon
Oberon, as imaged by Voyager 2, January 1986. A number of bright-rayed craters are visible, with the largest, Hamlet, at center. At the lower left limb rises an 11 km high mountain.
Discovery
Discovered byWilliam Herschel
Discovery dateJanuary 11, 1787[1]
Designations
Designation
Uranus IV
Pronunciation/ˈoʊbərɒn/ or /ˈoʊbərən/[2]
AdjectivesOberonian /ɒbəˈroʊniən/[3]
Orbital characteristics
583520 km[4]
Eccentricity0.0014[4]
13.463234 d[4]
Average orbital speed
3.15 km/s (calculated)
Inclination0.058° (to Uranus's equator)[4]
Satellite ofUranus
Physical characteristics
Mean radius
761.4±2.6 km (0.1194 Earths)[5]
7285000 km2[a]
Volume1849000000 km3[b]
Mass(3.1104±0.0749)×1021 kg[7]
Mean density
1.682 g/cm3 (calculated)
Surface gravity
0.358 m/s²[c]
0.738 km/s[d]
Synodic rotation period
presumed synchronous[8]
Albedo
  • 0.31 (geometrical)
  • 0.14 (Bond)[9]
Temperature70–80 K[10]
14.1[11]

Oberon /ˈoʊbərɒn/, also designated Uranus IV, is the outermost and second-largest major moon of the planet Uranus. It is the second-most massive of the Uranian moons, and the tenth-largest moon in the Solar System. Discovered by William Herschel in 1787, Oberon is named after the mythical king of the fairies who appears as a character in Shakespeare's A Midsummer Night's Dream. Its orbit lies partially outside Uranus's magnetosphere.

Oberon likely formed from the accretion disk that surrounded Uranus just after the planet's formation. The moon consists of approximately equal amounts of ice and rock, and is probably differentiated into a rocky core and an icy mantle. A layer of liquid water may be present at the boundary between the mantle and the core. The surface of Oberon, which is dark and slightly red in color, appears to have been primarily shaped by asteroid and comet impacts. It is covered by numerous impact craters reaching 210 km in diameter. Oberon possesses a system of chasmata (graben or scarps) formed during crustal extension as a result of the expansion of its interior during its early evolution.

The Uranian system has been studied up close only once: the spacecraft Voyager 2 took several images of Oberon in January 1986, allowing 40% of the moon's surface to be mapped.

  1. ^ Cite error: The named reference Herschel 1787 was invoked but never defined (see the help page).
  2. ^ "Oberon". Merriam-Webster.com Dictionary. Merriam-Webster.
  3. ^ Normand (1970) Nathaniel Hawthorne
  4. ^ a b c d Cite error: The named reference orbit was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Thomas 1988 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference French et al. 2024 was invoked but never defined (see the help page).
  7. ^ Jacobson (2023), as cited in French et al. (2024)[6]
  8. ^ Cite error: The named reference Smith Soderblom et al. 1986 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Karkoschka 2001, Hubble was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Grundy Young et al. 2006 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Newton Teece 1995 was invoked but never defined (see the help page).


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