Once qualified as the largest known → asteroid,
Ceres is now classified as a
→ dwarf planet (2006 IAU General Assembly). It is
approximately 950 km across, and resides
with tens of thousands of asteroids in the main
→ asteroid belt; it is
the largest body of the belt. Its mass is 9.4 × 1020 kg,
its → rotation period 9.074 hours, its
→ orbital period 4.60 years, and
its → semi-major axis 2.767 AU.
NASA’s → Dawn spacecraft,
which was placed in orbit around Ceres in
2015, has mapped its surface in great detail
from a distance. Dawn caught
sight of bright spots that soon resolved into more than 130 bright
patches, most of them tied to craters. The most
prominent of these spots lie inside the crater → Occator.
The patches turned out to be carbonate salts, which only form in
the presence of water. Since water skips to gas almost immediately on
the dwarf planet’s surface, the discovery of carbonates suggested that
there was liquid beneath the dwarf planet’s crust.
Aside from craters, the only outstanding feature On Ceres is a single mountain,
Ahuna Mons. It formed about 250 million years ago
when plumes of saltwater and mud rose and erupted from within Ceres.
Etymology (EN): Ceres in Roman mythology was the goddess of growing plants
and of motherly love. She was equivalent to Demeter in Gk. mythology.
