Oberon

Uranus IV

Oberon Facts

• Oberon is the outermost of Uranus's known satellites and second largest:
  • distance from Uranus: 583,420 km
  • diameter: 1523 km
  • mass: 3.03e21 kg

• Pronounced "OH buh ron".

• Oberon is the King of the Fairies and husband of Titania in Shakespeare's Midsummer-Night's Dream.

• Discovered by Herschel in 1787.

• Oberon and Umbriel appear quite similar though Oberon is 35% larger. All of Uranus's large moons are a mixture of about 40-50% water ice with the rest rock, a somewhat larger fraction of rock than Saturn's large moons such as Rhea.

• Oberon's heavily cratered surface has probably been stable since its formation. It has far more and larger craters than do Ariel and Titania. Some of the craters have rays of ejecta similar to those seen on Callisto.

• Some of the crater floors are dark, perhaps covered with darker material (dirty water?) that upwelled into the crater.

• Large faults are also seen across the entire southern hemisphere of Oberon. This indicates some geologic activity early in Oberon's history.

• The picture above shows a mountain on the limb that rises 6 km above its surrounds.

Pictures

1. (above) 167k gif; 12k jpg;
2. Oberon: color large low res 60k jpg

More about Oberon

• from LANL

Open Issues

• Why have Oberon and Umbriel apparently been inactive throughout their histories while Ariel and Titania have been at least partially resurfaced?