Object Analysis

Oberon is the outermost and second-largest of the major moons of Uranus. It was discovered by William Herschel in 1787. Like Titania, it is composed of roughly equal parts rock and ice. Its surface is dark and heavily cratered, showing a red tint that is likely caused by the long-term irradiation of organic materials.

Oberon has the most cratered surface of all the Uranian moons, with some craters reaching 210 kilometers in diameter. Many of the larger craters have dark floors, which may be deposits of "cryovolcanic" material that welled up from the interior after the impacts. It also features a massive mountain, rising roughly 11 kilometers from the surface, seen on the moon's limb in Voyager 2 images.

Because it is the outermost major moon, Oberon is the least affected by the tidal forces of Uranus. This has left it geologically "dead" for billions of years, making it a pristine record of the early outer solar system. Its distance from Uranus also means it is the moon least likely to harbor any liquid water in its interior today.