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)
Naming of moons is the latter's number in parentheses. Thus, Dactyl, the moon of 243 Ida, was at first designated "S/1993 (243) 1". Once confirmed and named, it became (243) Ida I Dactyl. Similarly, the fourth satellite of Pluto, Kerberos, discovered after Pluto was categorized as a dwarf planet and assigned a minor planet number, was designated S/2011 (134340) 1 rather than S/2011 P 1, though the New Horizon team, who disagreed with the dwarf planet classification, used the latter. After a few months or years, when a newly discovered satellite's existence has been confirmed and its orbit computed, a permanent name is