Ceres is the first bare asteroid. This spatial object 950 kilometers in diameter is situated in the main belt of asteroids between Mars and Jupiter. It is spherical, and enough massif to be raised to the rank of dwarfish planet in the same way as Pluto and Eris. The name of Ceres girl of Saturn and Ops (either of Vesta or Cybele) taught to the men the art to cultivate the ground, to sow), to harvest the wheat, and to make it some bread, what made consider it as the goddess of the agriculture. Jupiter, her brother, been in love his beauty, had of her Proserpine (likened to Persephone of the Greek mythology). She was also liked by Neptune, and, to escape her pursuit, she changed in mare. The god noticed it and metamorphosed into horse. The courtship of Neptune made her a mother of the horse Arion.   is pulled by the Roman mythology, the goddess of the agriculture, the harvests and the fertility, associated with the Greek goddess Demeter.

Diameter 959,2×932,6 km
Masse 9,445×1020 kg
Density 2,05×103 kg/m³
Gravity 0,26 m/s²
Escape speed 0,51 km/s
Period of rotation 0,3781 d
Magnitude absolute 3,34
Albedo 0,113
Temperature à la surface ~167 K

Ceres was a conscript Hera by the German astronomers. After its discovery, it had during almost 50 years the status of planet. With a mass of 9,445×1020 kg, Ceres concentrates to it only a third party of the total mass of the belt of asteroids - although it represents only approximately 3 % of the mass of the Moon. Ceres was observed for the first time on January 1st, 1801 by Giuseppe Piazzi, director of the observatory from Palermo to Sicily. This one suggested baptizing it Ceres Ferdinandea by attaching the name of the goddess defender of Sicily to that of king of the island Ferdinand III de Sicily,

his sponsor, then taken refuge in Palermo. Because of its position in the belt of asteroid main dynamics, its surface is probably heavily craterised. If Ceres has big craters, they must be "relaxed", meaning that their shape became leveled in the time, with the gravity. Such relaxed craters are very common on the icy moons of Jupiter and Saturn.

Giuseppe Piazzi, director of the observatory from Palermo to Sicily.

Characteristics

category : dwarf planets

An eclipse of a star by Ceres was observed in Mexico and in Florida on November 13th, 1984. In 2001, the spatial telescope Hubble photographed Ceres and we distinguish a dark point there on surface, which is probably a crater. We baptized it "Piazzi". The telescope Keck also revealed two large-sized dark zones. With Vesta, Ceres constitutes one of the next two objectives of the probe Dawn, which should be launched in 2007 and to reach it in 2015.