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
Astrobiology restricted to the surfaces of planets. The three most likely candidates for life in the Solar System are the planet Mars, the Jovian moon Europa, and Saturn's moons Titan, and Enceladus. Mars, Enceladus and Europa are considered likely candidates in the search for life primarily because they may have underground liquid water, a molecule essential for life as we know it for its use as a solvent in cells. Water on Mars is found frozen in its polar ice caps, and newly carved gullies recently observed on Mars suggest that liquid water may exist, at least transiently, on the planet's