1 Ceres (asteroid 1 -- See-reez) is the largest asteroid, and also the first to be discovered, with a diameter of 1003 km, and a surface area of 1,800,000 km2. 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).
With a mass of 8.7×1020kg, Ceres comprises over one-third the 2.3×1021 kg estimated total mass of all the asteroids.
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 History Discoverer G. Piazzi, 1801