Natural satellite achieved hydrostatic equilibrium, and Uranus has five. It has been suggested that some satellites may potentially harbour life. Among the identified dwarf planets, Ceres has no known natural satellites. Pluto has the relatively large natural satellite Charon and four smaller natural satellites; Styx, Nix, Kerberos, and Hydra. Haumea has two natural satellites, and Eris and Makemake have one each. The Pluto–Charon system is unusual in that the center of mass lies in open space between the two, a characteristic sometimes associated with a double-planet system. The seven largest natural satellites in the Solar System (those bigger than 2,500 km across)
Dwarf planet list of hundreds of candidate objects, ranging from "nearly certain" to "possible" dwarf planets."" As of Feb 2018, Brown's list includes 952 objects, identifying ten known trans-Neptunian objects—the four accepted by the IAU plus the six bodies: , , , , and —as "near certain", with another 26 "highly likely". Notably, (1535 km) has a larger diameter than the dwarf planet Makemake (1430 km). Stern states that there are more than a dozen known dwarf planets. Only two of these bodies, Ceres and Pluto, have been observed in enough detail to demonstrate that they actually fit the IAU's definition. The