“Mission scientists determined the deposits originated in a deep, global underground ocean of salty water. Based on Ceres’s gravity, they analyzed its internal structure and concluded its subsurface ocean is several hundred miles wide and around 25 miles (40 km) deep.”
“Oceans should be common features of dwarf planets based on what New Horizons learned at Pluto and Dawn at Ceres,” Dawn project scientist Julie Castillo-Rogez of NASA’s Jet Propulsion Laboratory (JPL) said in an interview with Astronomy magazine.”
Ice on the Moon 