Ceres is a dwarf planet.
Ahuna Mons [ @ ` hu:n@_'mQnz ] is the largest mountain on the dwarf planet and asteroid Ceres . Ceres (dwarf planet) . Its diameter is approximately 945 km , making it the largest of the minor planets within the orbit of Neptune . The 33rd-largest known body in the Solar System , it is the only dwarf planet within the orbit of Neptune.Due to its eccentric orbit , the dwarf planet Pluto was also within the orbit of Neptune from 1979 to 1999 , and will be again from approximately 2227 to 2247 . As the largest body in the asteroid belt , the dwarf planet Ceres ( formally `` 1 Ceres '' ) frequently appears in science fiction : Dawn (spacecraft) . It is currently in orbit about its second target , the dwarf planet Ceres .