Ceres (dwarf planet)

dwarf planet in the Solar System and largest asteroid of the main asteroid belt

Ceres, also known as 1 Ceres (symbol: ⚳),[12] is the smallest dwarf planet in the Solar System and the only one in the main asteroid belt.

Ceres ⚳
Ceres, photographed by the Dawn mission
Discovered byGiuseppe Piazzi
Discovery dateJanuary 1, 1801
MPC designation1 Ceres
A899 OF; 1943 XB
dwarf planet
main belt
Orbital characteristics
Epoch November 26, 2005
(JD 2453700.5)[1]
Aphelion447,838,164 km
2.987 AU
Perihelion381,419,582 km
2.544 AU
414,703,838 km
2.765 956 424 AU[2]
1679.819 days
4.599 years
17.882 km/s
Physical characteristics
Mean radius
473 km[3]
Flattening0.067 ± 0.005
Mass9.46 ± 0.04×1020 kg[4][5]
Mean density
2.08 g/cm3[6]
Equatorial surface gravity
0.27 m/s²
0.028 g
Equatorial escape velocity
0.51 km/s
0.3781 d
9.074 h[7]
0.113 (geometric)[8]
Surface temp. min mean max
Kelvin ~167 K[11] 239 K[11]
6.7 to 9.32
0.84"[10] to 0.33"

It was discovered on 1 January 1801, by Giuseppe Piazzi,[13] and is named after the Roman goddess Ceres, as the goddess of growing plants, the harvest, and motherly love. After about 200 years from its discovery, the International Astronomical Union decided to upgrade Ceres from an asteroid (or minor planet) to dwarf planetary status in 2006.

With a diameter of about 950 km, Ceres is by far the largest and most massive object in the asteroid belt, and has about a third of the belt's total mass. It was once thought to be smaller than Vesta, which is brighter. The asteroid is spherical, unlike the irregular shapes of smaller bodies with lower gravity. At its brightest it is still too dim to be seen with the naked eye.[14] Ceres is located at 2.8 AU (257 million miles) from the Sun, which makes it the closest dwarf planet to the Sun. It is also the only dwarf planet in the Solar System that has no moons.

On September 27, 2007, NASA launched the Dawn space probe to explore Ceres and Vesta. In 2015, Dawn became the first spacecraft to visit a dwarf planet, arriving at Ceres a few months before NASA's New Horizons spacecraft visited Pluto, another dwarf planet.

Ceres has an unusual crater, Occator which contains bright salts.


Close up image of bright salts, imaged by the Dawn spacecraft, in the crater Occator on Ceres.


  1. Ted Bowell, Bruce v (January 2, 2003). "Asteroid Observing Services". Lowell Observatory. Retrieved 2007-01-17.
  2. 2.0 2.1 2.2 2.3 2.4 Yeomans, Donald K. (July 5, 2007). "1 Ceres". JPL Small-Body Database Browser. Retrieved 2007-07-05.—The listed values were rounded at the magnitude of uncertainty (1-sigma).
  3. "05. Dawn Explores Ceres Results from the Survey Orbit.pptx".
  4. Pitjeva, E.V. (2005). "High-Precision Ephemerides of Planets—EPM and Determination of Some Astronomical Constants" (PDF). Solar System Research. 39 (3): 176–186. Bibcode:2005SoSyR..39..176P. doi:10.1007/s11208-005-0033-2. S2CID 120467483. Archived from the original (PDF) on 2012-09-07. Retrieved 2007-11-01.
  5. D. T. Britt | display-authors = etal Asteroid density, porosity, and structure, pp. 488 in Asteroids III, University of Arizona Press (2002).
  6. Thomas, P.C.; Parker J.Wm. and McFadden, L.A.; et al. (2005). "Differentiation of the asteroid Ceres as revealed by its shape". Nature. 437 (7056): 224–226. Bibcode:2005Natur.437..224T. doi:10.1038/nature03938. PMID 16148926. S2CID 17758979.
  7. Harris, A.W. (2006). Warner, B.D. and Pravec, P. (ed.). "Asteroid Lightcurve Derived Data. EAR-A-5-DDR-DERIVED-LIGHTCURVE-V8.0". NASA Planetary Data System. Retrieved 2007-03-15.{{cite web}}: CS1 maint: multiple names: editors list (link)
  8. 8.0 8.1 Tedesco, E.F. (2004). "IRAS Minor Planet Survey. IRAS-A-FPA-3-RDR-IMPS-V6.0". Noah, P.V.; Noah, M.; Price, S.D. Planetary Data System. Retrieved 2007-03-15.
  9. Neese, C., ed. (2005). "Asteroid Taxonomy.EAR-A-5-DDR-TAXONOMY-V5.0". NASA Planetary Data System. Retrieved 2007-03-15.
  10. Ceres Angular Size @ Feb 2009 Opposition: 974km dia / (1.58319AU * 149 597 870km) * 206265 = 0.84"
  11. 11.0 11.1 Saint-Pé, O.; Combes, N. and Rigaut F. (1993). "Ceres surface properties by high-resolution imaging from Earth". Icarus. 105 (2): 271–281. Bibcode:1993Icar..105..271S. doi:10.1006/icar.1993.1125.
  12. JPL/NASA (2015-04-22). "What is a Dwarf Planet?". Jet Propulsion Laboratory. Retrieved 2022-01-19.
  13. Piazzi, Giuseppe (1801). Risultati delle osservazioni della nuova Stella scoperta il dì 1 gennajo all'Osservatorio Reale di Palermo (in Italian). Palermo.
  14. Ceres at Solarviews.com