Ceres (dwarf planet)
|Discovered by||Giuseppe Piazzi|
|Discovery date||January 1, 1801|
|MPC designation||1 Ceres|
|A899 OF; 1943 XB|
|Epoch November 26, 2005|
2.765 956 424 AU
Average orbital speed
|Flattening||0.067 ± 0.005|
|Mass||9.46 ± 0.04×1020 kg|
Equatorial surface gravity
Equatorial escape velocity
Sidereal rotation period
|6.7 to 9.32|
|0.84" to 0.33"|
It was discovered on 1 January 1801, by Giuseppe Piazzi, and is named after the Roman goddess Ceres, as the goddess of growing plants, the harvest, and of 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.
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.
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- 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).
- "05. Dawn Explores Ceres Results from the Survey Orbit.pptx".
- Pitjeva, E.V. (2005). "High-Precision Ephemerides of Planets—EPM and Determination of Some Astronomical Constants" (PDF). Solar System Research 39 (3): 176. doi:10.1007/s11208-005-0033-2. http://iau-comm4.jpl.nasa.gov/EPM2004.pdf.
- D. T. Britt et al. Asteroid density, porosity, and structure, pp. 488 in Asteroids III, University of Arizona Press (2002).
- 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: 224-226. doi:10.1038/nature03938. http://adsabs.harvard.edu/abs/2005Natur.437..224T.
- 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.CS1 maint: Multiple names: editors list (link)
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- Ceres Angular Size @ Feb 2009 Opposition: 974km dia / (1.58319AU * 149 597 870km) * 206265 = 0.84"
- Saint-Pé, O.; Combes, N. and Rigaut F. (1993). "Ceres surface properties by high-resolution imaging from Earth". Icarus 105: 271-281. doi:10.1006/icar.1993.1125. http://adsabs.harvard.edu/abs/1993Icar..105..271S.
- Piazzi, Giuseppe (1801). Risultati delle osservazioni della nuova Stella scoperta il dì 1 gennajo all'Osservatorio Reale di Palermo (in Italian). Palermo.
- Ceres at Solarviews.com