Ceres is the largest object in the asteroid belt. It orbits the Sun between Mars and Jupiter and is officially classified as a dwarf planet as well as a minor planet.
Giuseppe Piazzi discovered Ceres on January 1, 1801, from Palermo, Sicily. It was initially announced as a new planet, but later became the prototype for the category of asteroids after many similar objects were found in the same region. The discovery of Pluto and the modern dwarf-planet definition eventually gave Ceres its present classification.
Ceres has a mean diameter of about 939 kilometers and contains roughly 40 percent of the estimated mass of the main asteroid belt. Its rounded shape reflects enough gravity to pull it toward hydrostatic equilibrium, although it is far smaller than Earth’s Moon.
The NASA Dawn spacecraft studied Ceres from orbit beginning in 2015. Dawn revealed bright deposits, salty mineral evidence, clay-rich surface material, and signs that Ceres contains substantial water ice. Ceres is therefore more than a large rocky asteroid: it is a chemically and geologically complex dwarf planet.