Moons of Uranus: names, categories, and a complete list

Uranus has 27 confirmed natural satellites, a collection that ranges from large, geologically complex bodies to tiny irregular capture objects. The ensemble is conventionally catalogued by orbital distance or orbital period; many popular lists are ordered by how long each moon takes to complete one orbit (orbital period). Unlike the mythological names used for many other planets’ satellites, Uranus’ moons are named after characters from works of literature — principally plays by William Shakespeare and characters from Alexander Pope — a convention reflected in scientific catalogs and public references (naming).

Characteristics: Five principal moons — Miranda, Ariel, Umbriel, Titania and Oberon — dominate by size and retain varied terrains indicating past geological activity on some. These larger moons are composed mainly of water ice mixed with rock. The remaining satellites fall into two broad groups: a set of small inner moons that orbit close to Uranus and interact with its ring system, and a population of distant irregular moons with eccentric, often retrograde orbits that are likely captured objects.

Discovery and exploration: The first of Uranus’ satellites were found in the late 18th and 19th centuries: Titania and Oberon were reported by William Herschel in 1787, Ariel and Umbriel by William Lassell in 1851, and Miranda by Gerard Kuiper in 1948. The Voyager 2 flyby in 1986 provided the only close-up imagery to date, revealing details of surfaces and discovering additional small moons. Many tiny outer moons were identified with improved ground-based telescopes and space-based instruments in the late 20th and early 21st centuries.