Ceres

Ceres

Dwarf Planet· orbits the Sun

Ceres is the largest object in the asteroid belt and the only dwarf planet in the inner Solar System. It is rich in water ice and bright salt deposits, studied in detail by NASA's Dawn mission.

Open in 3D viewSee Ceres in the live, interactive 3D map

Key facts

Mass
9.38 × 10²⁰ kg
0.0128 Moon masses
Radius
470 km
7% of Earth's radius
Surface gravity
0.284 m/s²
3% of Earth's
Day length
9.07 hours
Year
4.6 Earth years
1,680 Earth days
Distance from Sun
2.77 AU
Moons
None

Science

Physical

Mass
9.38 × 10²⁰ kg · 0.0128 Moon masses
Radius
470 km · 7% of Earth's radius
Density
2,162 kg/m³ · 2.2× water
Surface gravity
0.284 m/s² · 3% of Earth's
Escape velocity
516 m/s · 5% of Earth's
Axial tilt
4.00 °

Orbital

Distance from the Sun
2.71 AU
Semi-major axis
2.77 AU
Eccentricity
0.07973
Inclination
27.19 °
Orbital period
4.60 years
Perihelion
2.55 AU
Aphelion
2.99 AU
Mean orbital velocity
17.9 km/s

Rotation

Rotation period
9.07 hours

Temperature

Mean
168 K (-105 °C)

Composition

Bulk composition
Rocky core with a water-ice-rich mantle and salt deposits

Radiation & temperature

Insolation
0.131 S⊕ · 13% of the sunlight Earth receives
Bond albedo
0.09 · reflects 9% of incoming sunlight
Equilibrium temperature
163 K (-110 °C)
Measured mean temperature
168 K (-105 °C)

Discovery & history

Discovered
January 1, 1801
By
Giuseppe Piazzi
Method
Visual discovery (telescopic)
Name
The Roman goddess of agriculture and patron of Sicily, where it was found.

Ceres was discovered on the first night of the 19th century, 1 January 1801, by Giuseppe Piazzi in Palermo. Hailed as a new planet filling the 'gap' between Mars and Jupiter, it was soon joined by Pallas, Juno and Vesta, and the four were reclassified as 'asteroids'. Ceres is by far the largest, and in 2006 it was promoted to dwarf planet. The Dawn spacecraft orbited it in 2015.

  1. 2015DawnOrbiter

    First spacecraft to orbit a dwarf planet; studied the bright salt deposits in Occator crater.

Images

Ceres in colour, imaged by Dawn
NASA / JPL-Caltech / UCLA / MPS / DLR / IDA (public domain) · Wikimedia Commons
Samhain Catenae on Ceres
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA · NASA Image Library
High Resolution Ceres View
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA · NASA Image Library
Clues to Ceres' Internal Structure
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA · NASA Image Library
Map of Ceres' Bright Spots
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI/Caltech · NASA Image Library
Dawn Navigating Ceres
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA · NASA Image Library
Dawn: On its Way to Low Orbit
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA · NASA Image Library
Kokopelli Crater on Ceres
NASA/JPL-Caltech/UCLA/MPS/DLR/IDA · NASA Image Library

Images from open archives · credit shown per image