Moons of Uranus these five, Titania, is 1,578 km in diameter and the eighth-largest moon in the Solar System, and about one-twentieth the mass the Earth's Moon. The orbits of the regular moons are nearly coplanar with Uranus's equator, which is tilted 97.77° to its orbit. Uranus's irregular moons have elliptical and strongly inclined (mostly retrograde) orbits at large distances from the planet. William Herschel discovered the first two moons, Titania and Oberon, in 1787, and the other three ellipsoidal moons were discovered in 1851 by William Lassell (Ariel and Umbriel) and in 1948 by Gerard Kuiper (Miranda). These five have planetary mass,
Minor-planet moon uncertain. There are 5 Jupiter trojans with a moon. Candidate binaries with an unconfirmed status are displayed on a dark background. There are only 2 centaurs with satellites, both of which are ring systems instead of moons. There are 87 trans-Neptunian objects known to have moons, with a total of 93 moons discovered. Candidate binaries with an unconfirmed status are displayed on a dark background. Minor-planet moon A minor-planet moon is an astronomical object that orbits a minor planet as its natural satellite. It is thought that many asteroids and Kuiper belt objects may possess moons, in some cases quite