- MEAN RADIUS: 487.3 km
- MASS: 0.013 (Earth=1)
- DENSITY: 2.077 (g/cm^3)
- GRAVITY: 0.028 (Earth=1)
- ORBIT PERIOD: 1679.819 (Earth days)
- ROTATION PERIOD: 0.3781 (Earth days)
- SEMIMAJOR AXIS OF ORBIT: 2.765 au
- ECCENTRICITY OF ORBIT: 0.07976017
Named after the Roman goddess of the harvest, of growing plants, and motherly love, Ceres is the smallest of the dwarf planets, a new category of astronomical bodies created by the International Astronomical Union in 2006. That event, including the demotion of Pluto was not the first of its kind. After the discovery of Ceres, it was first designated as a planet and named Ceres Ferdinandea, after the Roman and Sicilian goddess of grain and King Ferdinand IV of Naples and Sicily. The name Ferdinandea did not sit well with other nations so it was soon dropped. Then, as other objects were discovered in a roughly similar orbit, Ceres's designation was eventually changed from planet to a new term, asteroid.
Based on studies using observations by the Hubble Space telescope, scientists have determined that Ceres has a very primitive surface. It may have a differentiated internal structure, with a separate mantle layer containing water-ice surrounding a rocky core and possibly a very weak atmosphere and frost. Surface temperatures on Ceres may reach a relatively warm -38 degrees C.