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1 Ceres

1 Ceres
Orbital characteristics
Orbit type Main belt
Semimajor axis 2.767 AU
Eccentricity 0.0789
Orbital period 4.60 Years
Inclination 10.58°
Physical characteristics
Diameter 940-1,003 km
Mass 8.7×1020 kg
Density 2.7 g/cm3
Rotation period 9h 4m
Spectral class C
Albedo 0.073
Discoverer G. Piazzi, 1801

1 Ceres (asteroid 1 -- See-reez) was the first asteroid to be discovered, with a diameter of 1003 km, and a surface area of 1,800,000 km2. It was discovered on January 1, 1801, by Giuseppe Piazzi, and originally named Ceres Ferdinandea after the Classical Greek and Sicilian goddess of plants and motherly love and King Ferdinand IV of Naples and Sicily. The Ferdinandea part was dropped for political reasons. For two hundred years, it was the largest known asteroid in the Solar System, until the 2001 discovery of 28978 Ixion.

With a mass of 8.7×1020kg, Ceres comprises over one-third the 2.3×1021 kg estimated total mass of all the asteroids.