::Ceres (dwarf planet)


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Ceres ({{#invoke:IPAc-en|main}};<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> minor-planet designation: 1 Ceres) is the largest object in the asteroid belt, which lies between the orbits of Mars and Jupiter. Its diameter is approximately {{safesubst:#invoke:convert|convert}},<ref name=presentation/> making it the largest of the minor planets within the orbit of Neptune. The thirty-third largest known body in the Solar System, it is the only one identified orbiting entirely within the orbit of Neptune that is a dwarf planet.<ref name="PBE-20150215">{{#invoke:citation/CS1|citation |CitationClass=news }}</ref> Composed of rock and ice, Ceres is estimated to comprise approximately one third of the mass of the entire asteroid belt. Ceres is the only object in the asteroid belt known to be unambiguously rounded by its own gravity. From Earth, the apparent magnitude of Ceres ranges from 6.7 to 9.3, and hence even at its brightest, it is too dim to be seen with the naked eye, except under extremely dark skies.

Ceres was the first asteroid discovered, by Giuseppe Piazzi at Palermo on 1 January 1801. It was originally considered a planet, but was reclassified as an asteroid in the 1850s when many other objects in similar orbits were discovered.

Ceres appears to be differentiated into a rocky core and icy mantle, and may harbor a remnant internal ocean of liquid water under the layer of ice.<ref name = "McCord2005-jgrp">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref><ref name = "O'Brien2015"/> The surface is probably a mixture of water ice and various hydrated minerals such as carbonates and clay. In January 2014, emissions of water vapor were detected from several regions of Ceres.<ref>NASA Science News: Water Detected on Dwarf Planet Ceres , by Production editor: Dr. Tony Phillips | Credit: [email protected] (22 January 2014)</ref> This was unexpected, because large bodies in the asteroid belt do not typically emit vapor, a hallmark of comets.

The robotic NASA spacecraft Dawn entered orbit around Ceres on 6 March 2015.<ref name="NASA-20150306">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name = "Rayman2015.03.06">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Pictures with a resolution previously unattained were taken during imaging sessions starting in January 2015 as Dawn approached Ceres, showing a cratered surface. Two distinct bright spots (or high-albedo features) inside a crater, incorrectly reported as observed in earlier Hubble images,<ref name="SL-20150511">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> were seen in a 19 February 2015 image, leading to speculation about a possible cryovolcanic origin<ref name = "O'Neill2015.02.25">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name = "Landau2015.02.25">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name = "Lakdawalla2015.02.26">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> or outgassing.<ref name="">[1]</ref> On 3 March 2015, a NASA spokesperson said the spots are consistent with highly reflective materials containing ice or salts, but that cryovolcanism is unlikely.<ref name="UT-20150303">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> On 11 May 2015, NASA released a higher resolution image showing that, instead of one or two spots, there are actually several.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Ceres (dwarf planet) sections
Intro  History  Physical characteristics  Orbit  Origin and evolution  Potential habitability  Observation  Exploration  Maps  Gallery  See also  Notes  References  External links  

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