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'@@ -1,97 +1,390 @@ -{{wiktionary|Ceres|ceres}} -'''Ceres''' commonly refers to: -* [[Ceres (dwarf planet)]], closest of the five identified dwarf planets, the only asteroid that is a dwarf planet -* [[Ceres (mythology)]], the Roman goddess of agriculture +{{Use dmy dates|date=January 2014}} +{{Infobox planet +| bgcolour = #FFFFC0 +| name = Ceres +| symbol= [[File:Ceres symbol.svg|25px|⚳]] +| image = [[File:PIA19562-Ceres-DwarfPlanet-Dawn-RC3-image19-20150506.jpg|250px]] +| caption = Ceres viewed by the [[Dawn (spacecraft)|''Dawn'']] spacecraft on 6 May 2015 at a distance of {{convert|13600|km|mi|abbr=on}} +| discovery = yes +| discovery_ref =<ref>{{cite book |last=Schmadel |first=Lutz |authorlink=Lutz D. Schmadel |title=Dictionary of minor planet names |url=http://books.google.com/?id=KWrB1jPCa8AC&pg=PA15 |edition=5th |year=2003 |publisher=Springer |location=Germany |isbn=978-3-540-00238-3 |page=15 }}</ref> +| discoverer = [[Giuseppe Piazzi]] +| discovered = 1 January 1801 +| designations = yes +| mp_name = '''1 Ceres''' +| pronounced = {{IPAc-en|ˈ|s|ɪər|iː|z}} +| named_after = [[Ceres (mythology)|Cerēs]] +| alt_names = A899 OF; 1943 XB +| adjectives = Cererian {{IPA|/sɨˈrɪəri.ən/}},<br>rarely Cererean {{IPA|/sɛrɨˈriːən/}}<ref name="Simpson1979">{{cite book |last=Simpson |first=D. P. |title=Cassell's Latin Dictionary |publisher=Cassell Ltd |year=1979 |edition=5th |location=London |isbn=978-0-304-52257-6 |page=883 }}</ref> +| mp_category = [[dwarf planet]]<br>[[main belt]] +| orbit_ref =<ref name="jpl_sbdb">{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Ceres |title=1 Ceres |publisher=JPL Small-Body Database Browser |accessdate=8 January 2015 |archiveurl=http://www.webcitation.org/69fuVB1N8 |archivedate=4 August 2012 |deadurl=no }}</ref> +| epoch = 2014-Dec-09<br>([[Julian day|JD]] {{val|2457000.5}}) +| aphelion = {{val|2.9773|ul=AU}} <br>({{val|445410000|u=km}}) +| perihelion = {{val|2.5577|u=AU}} <br>({{val|382620000|u=km}}) +| semimajor = {{val|2.7675|u=AU}} <br>({{val|414010000|u=km}}) +| eccentricity = {{val|0.075823}} +| period = 4.60&nbsp;[[julian year (astronomy)|yr]]<br>1681.63&nbsp;d +| synodic_period = 466.6&nbsp;[[Julian day|d]]<br>1.278&nbsp;[[julian year (astronomy)|yr]] +| inclination = {{val|10.593|u=°}} to [[ecliptic]]<br>9.20° to [[invariable plane]]<ref name="meanplane">{{cite web |date=3 April 2009 |title=The MeanPlane (Invariable plane) of the Solar System passing through the barycenter |url=http://home.surewest.net/kheider/astro/MeanPlane.gif |accessdate=10 April 2009 |archiveurl=http://www.webcitation.org/5glwILykY |archivedate=14 May 2009 |deadurl=no}} (produced with [http://chemistry.unina.it/~alvitagl/solex/ Solex 10] written by Aldo Vitagliano; see also [[Invariable plane]])</ref> +| arg_peri = {{val|72.5220|u=°}} +| asc_node = {{val|80.3293|u=°}} +| mean_anomaly = {{val|95.9891|u=°}} +| avg_speed = {{val|17.905|u=km/s}} +| p_orbit_ref =<ref name="Ceres-POE">{{cite web |title=AstDyS-2 Ceres Synthetic Proper Orbital Elements |publisher=Department of Mathematics, University of Pisa, Italy |url=http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.6&n=1 |accessdate=1 October 2011 |archiveurl=http://www.webcitation.org/62D4xP3TU |archivedate=5 October 2011 |deadurl=no }}</ref> +| p_semimajor = {{val|2.7670962}} +| p_eccentricity = {{val|0.1161977}} +| p_inclination = {{val|9.6474122|u=°}} +| p_mean_motion = 78.193318 +| perihelion_rate = {{val|54.070272}} +| node_rate = {{val|-59.170034}} +| satellites = None +| allsatellites=yes +| physical_characteristics = yes +| dimensions = {{nowrap|({{val|482.6}} × {{val|480.6}} × {{val|445.6}}) ± 1.0 km<ref name=presentation/>}} +| mean_radius = {{val|473|u=km}}<ref name=presentation/> +| surface_area = {{val|2770000|u=km2}}<ref name="fact2">Calculated based on the known parameters</ref> +| volume = {{val|421000000|u=km3}}<ref name="fact2" /> +| mass={{val|9.393|e=20|u=kg|0.005}}<ref name=presentation/><br> +{{val|0.00015|u=[[Earth mass|Earths]]}}<br>0.0128 [[Moon]]s +| density={{val|2.16|u=g/cm3}}<ref name=presentation>Chris Russel at [http://nesf2015.arc.nasa.gov/agenda]</ref> +|surface_grav = {{Gr|.939|469|2}} [[Acceleration|m/s²]]<ref name="fact2"/><br>0.029 [[g-force|''g'']] +| escape_velocity={{V2|0.943|476.2|2}}&nbsp;km/s<ref name="fact2" /> +| sidereal_day = {{val|0.3781|u=d}}<br>{{val|9.074170|0.000002|u=h}}<ref name="Chamberlain2007">{{cite journal |last1=Chamberlain |first1=Matthew A. |author2=Sykes, Mark V.; Esquerdo, Gilbert A. |year=2007 |title=Ceres lightcurve analysis – Period determination |journal=Icarus |volume=188 |issue=2 |pages=451–456 |doi=10.1016/j.icarus.2006.11.025 |bibcode=2007Icar..188..451C }}</ref> +| rot_velocity= {{val|92.61|u=m/s}}<ref name="fact2"/> +| right_asc_north_pole = 29.41°<ref name=presentation/> +| declination = 66.79°<ref name=presentation/> +| axial_tilt = ≈&thinsp;3°<ref name="Thomas2005" /> +| albedo={{val|0.090|0.0033}} ([[geometric albedo|V-band geometric]])<ref name="Li2006" /> +| temperatures = yes +| temp_name1 = [[Kelvin]] +| min_temp_1 = ? +| mean_temp_1 = ≈&thinsp;168&nbsp;K<ref>{{cite book |author=Angelo, Joseph A., Jr |year=2006 |title=Encyclopedia of Space and Astronomy |publisher=Infobase |location=New York |isbn=0-8160-5330-8 |page=122 }}</ref> +| max_temp_1 = 235&nbsp;K<ref name="Saint-Pe1993" /> +| spectral_type=[[C-type asteroid|C]]<ref name="Rivkin2006" /> +| magnitude = 6.64<ref name="Pasachoff1983" /> to 9.34<ref name="fact3" /> +| abs_magnitude ={{val|3.36|0.02}}<ref name="Li2006" /> +| angular_size = 0.854″ <!-- Horizons 1636-Feb-11 --> to 0.339″ +}} -'''Ceres''' may also refer to: +'''Ceres''' ({{IPAc-en|ˈ|s|ɪər|iː|z}};<ref>{{cite web |title=Ceres |work=Dictionary.com |publisher=Random House, Inc. |url=http://dictionary.reference.com/browse/ceres |accessdate=26 September 2007 |archiveurl=http://www.webcitation.org/62D65VxlL |archivedate=5 October 2011 |deadurl=no }}</ref> [[minor-planet designation]]: '''1 Ceres''') is the [[List of notable asteroids|largest object]] in the [[asteroid belt]], which lies between the orbits of [[Mars]] and [[Jupiter]]. Its diameter is approximately {{convert|945|km|abbr=off|sp=us}},<ref name=presentation/> making it the largest of the [[minor planet]]s within the orbit of [[Neptune]]. The thirty-third [[List of Solar System objects by size|largest known body]] in the [[Solar System]], it is the only one within the orbit of Neptune that is designated a [[dwarf planet]] by the [[International Astronomical Union]] (IAU).<ref name="PBE-20150215">{{cite news |last=Stankiewicz |first=Rick |title=A visit to the asteroid belt |url=http://www.thepeterboroughexaminer.com/2015/02/20/a-visit-to-the-asteroid-belt |date=20 February 2015 |work=[[Peterborough Examiner]] |accessdate=29 May 2015 }}</ref> Composed of rock and ice, Ceres is estimated to comprise approximately one third of the mass of the entire asteroid belt.<!-- 4.753±0.007 ÷ 15±2 (E-10 solar masses) = 28–35% --> Ceres is the only object in the asteroid belt known to be unambiguously [[hydrostatic equilibrium|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. -{{TOC right}} +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. -== Places == -===Brazil=== -* [[Ceres, Goiás]], Brazil -* [[Ceres Microregion]], in north-central Goiás state, Brazil +Ceres appears to be [[Planetary differentiation|differentiated]] into a [[Rock (geology)|rocky]] [[core (geology)|core]] and icy [[mantle (geology)|mantle]], and may harbor a remnant [[internal ocean]] of [[Extraterrestrial liquid water|liquid water]] under the layer of ice.<ref name = "McCord2005">{{cite journal |title=Ceres: Evolution and current state |journal=Journal of Geophysical Research: Planets |date=21 May 2005 |last=McCord |first=T. B. |last2=Sotin |first2=C. |volume=110 |issue=E5 |page=E05009 |doi=10.1029/2004JE002244 |url=http://onlinelibrary.wiley.com/doi/10.1029/2004JE002244/full |accessdate=7 March 2015 |bibcode = 2005JGRE..110.5009M }}</ref><ref name = "O'Brien2015"/> The surface is probably a mixture of [[Ice|water ice]] and various [[hydrate]]d minerals such as [[carbonate minerals|carbonates]] and [[clay mineral|clay]]. In January 2014, emissions of water vapor were detected from several regions of Ceres.<ref>NASA Science News: [http://science.nasa.gov/science-news/science-at-nasa/2014/22jan_ceres/ Water Detected on Dwarf Planet Ceres ], by Production editor: Dr. Tony Phillips | Credit: Science@NASA (22 January 2014)</ref> This was unexpected, because large bodies in the asteroid belt do not typically emit vapor, a hallmark of comets. -=== United States === -* [[Ceres, California]] -* [[Ceres Flat, California]] -* [[Ceres, Georgia]] -* [[Ceres, Iowa]]. a community in [[Clayton County, Iowa|Clayton County]] -* [[Ceres, New York]] -* [[Ceres, Oklahoma]], a community in [[Noble County, Oklahoma|Noble County]] -* [[Ceres, Virginia]] -* [[Ceres, Washington]], a community in [[Lewis County, Washington|Lewis County]] -* [[Ceres, West Virginia]] -* [[Ceres Township, McKean County, Pennsylvania]] +The robotic NASA spacecraft [[Dawn (spacecraft)|''Dawn'']] entered orbit around Ceres on 6 March 2015.<ref name="NASA-20150306">{{cite web |last1=Landau |first1=Elizabeth |last2=Brown |first2=Dwayne |title=NASA Spacecraft Becomes First to Orbit a Dwarf Planet |url=http://www.jpl.nasa.gov/news/news.php?feature=4503 |date=6 March 2015 |work=[[NASA]] |accessdate=6 March 2015 }}</ref><ref name="arrival-jpl.nasa.gov">{{cite web|title=Dawn Spacecraft Begins Approach to Dwarf Planet Ceres|url=http://www.nasa.gov/jpl/dawn/dawn-spacecraft-begins-approach-to-dwarf-planet-ceres/|accessdate=29 December 2014}}</ref><ref name = "Rayman2015.03.06">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/marc-rayman/20150306-dawn-journal-ceres-orbit-insertion.html |title=Dawn Journal: Ceres Orbit Insertion! |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=6 March 2015 |accessdate=6 March 2015}}</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 on Ceres|bright spots]] (or high-[[albedo]] features) inside a crater, incorrectly reported as observed in earlier Hubble images,<ref name="SL-20150511">{{cite web |last=Plait |first=Phil |title=The Bright Spots of Ceres Spin Into View |url=http://www.slate.com/blogs/bad_astronomy/2015/05/11/ceres_new_images_show_many_many_bright_spots.html |date=11 May 2015 |work=[[Slate (magazine)|Slate]] |accessdate=30 May 2015 }}</ref> were seen in a 19 February 2015 image, leading to speculation about a possible [[cryovolcanic]] origin<ref name = "O'Neill2015.02.25">{{cite web + | last = O'Neill | first = I. | title = Ceres' Mystery Bright Dots May Have Volcanic Origin + | publisher = [[Discovery Communications]] + | date = 25 February 2015 | accessdate = 1 March 2015 + | url = http://news.discovery.com/space/ceres-mystery-bright-dots-may-have-volcanic-origin-150225.htm + | archiveurl = | archivedate = }}</ref><ref name = "Landau2015.02.25">{{cite web + | last = Landau | first = E. | title = 'Bright Spot' on Ceres Has Dimmer Companion + | publisher = [[Jet Propulsion Laboratory]] + | date = 25 February 2015 | accessdate = 25 February 2015 + | url = http://dawn.jpl.nasa.gov/feature_stories/Bright_Spot_Ceres_Dimmer_Companion.asp + | archiveurl = | archivedate = }}</ref><ref name = "Lakdawalla2015.02.26">{{cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2015/02251857-ceres-geology.html |title= +At last, Ceres is a geological world |publisher=[[Planetary Society]] |first=E. |last=Lakdawalla | authorlink= Emily Lakdawalla| date=26 February 2015 |accessdate=26 February 2015}}</ref> or outgassing.<ref name="planetary.org">[http://www.planetary.org/blogs/emily-lakdawalla/2015/03191629-lpsc-2015-dawn-at-ceres.html]</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">{{cite web |last=Atkinson |first=Nancy |title=Bright Spots on Ceres Likely Ice, Not Cryovolcanoes |url=http://www.universetoday.com/119235/bright-spots-on-ceres-likely-ice-not-cryovolcanoes/ |date=3 March 2015 |work=[[Universe Today]] |accessdate=4 March 2015 }}</ref> On 11 May 2015, NASA released a higher resolution image showing that, instead of one or two spots, there are actually several.<ref>http://www.jpl.nasa.gov/spaceimages/details.php?id=pia19547</ref> -===Other countries=== -* [[Ceres, Santa Fe]], Argentina -* [[Ceres, Victoria]], Australia -* [[Ceres, Piedmont]], Italy -* [[Ceres, Fife]], Scotland -* [[Ceres, Western Cape]], South Africa -* [[Ceres Nunataks]], Antarctica -* [[Ceres Koekedouw Dam]], dam on the Koekedouw River, near Ceres, Western Cape, South Africa +==History== -== Acronyms == -* [[CERES (satellite)]] (Capacity de REnseignement Electromagnétique Spatial, Space-based electronic signals intelligence capability), a French spy satellite program -* [[California Environmental Resources Evaluation System]] -* [[Center for Eurasian, Russian, and East European Studies (CERES)|Center for Eurasian, Russian, and East European Studies]] at Georgetown University -* [[Centre for Research on Energy Security]] (CeRES), an Indian research center on geopolitics and energy -* [[CERES Community Environment Park]] (Centre for Education and Research in Environmental Strategies), a community environmental park in Melbourne, Australia. -* [[Clouds and the Earth's Radiant Energy System]], an ongoing NASA meteorological experiment. -* [[Coalition for Environmentally Responsible Economies]] -* ''{{lang|fr|Centre d'études, de recherches et d'éducation socialiste}}'' (French: Center of Socialist Studies, Research and Education), a left-wing political organization founded by [[Jean-Pierre Chevènement]] +===Discovery=== +[[File:Cerere Ferdinandea.gif|thumb|upright|left|Piazzi's book ''"Della scoperta del nuovo pianeta Cerere Ferdinandea"'' outlining the discovery of Ceres, dedicated the new "planet" to [[Ferdinand I of the Two Sicilies]].]] +[[Johann Elert Bode]], in 1772, first suggested that an undiscovered planet could exist between the orbits of [[Mars]] and [[Jupiter]].<ref name="hoskin" /> [[Johannes Kepler|Kepler]] had already noticed the gap between Mars and Jupiter in 1596.<ref name="hoskin" /> Bode based his idea on the [[Titius–Bode law]]—a now-discredited hypothesis [[Johann Daniel Titius]] first proposed in 1766—observing that there was a regular pattern in the semi-major axes of the orbits of known planets, marred only by the large gap between Mars and Jupiter.<ref name="hoskin" /><ref name="Hogg1948">{{cite journal |last=Hogg |first=Helen Sawyer |title=The Titius-Bode Law and the Discovery of Ceres |journal=Journal of the Royal Astronomical Society of Canada |volume=242 |pages=241–246 |year=1948 |bibcode=1948JRASC..42..241S }}</ref> The pattern predicted that the missing planet ought to have an orbit with a semi-major axis near 2.8 [[astronomical unit]]s (AU).<ref name="Hogg1948" /> [[William Herschel]]'s discovery of [[Uranus]] in 1781<ref name="hoskin" /> near the predicted distance for the next body beyond [[Saturn]] increased faith in the law of Titius and Bode, and in 1800, a group headed by [[Franz Xaver von Zach]], editor of the ''Monatliche Correspondenz'', sent requests to twenty-four experienced astronomers (dubbed the "celestial police"), asking that they combine their efforts and begin a methodical search for the expected planet.<ref name="hoskin" /><ref name="Hogg1948" /> Although they did not discover Ceres, they later found several large [[asteroid]]s.<ref name="Hogg1948" /> -==Aircraft, transport, and vessels== -* [[CAC Ceres]], a crop-duster aircraft manufactured in Australia -* [[West Cornwall Railway#Locomotives|Ceres]], a West Cornwall Railway steam locomotive -* [[HMS Ceres]], three ships of the British Royal Navy -* [[Toyota Corolla Ceres]] a compact, 4-door hardtop sold in Japan -* ''Céres'', a French [[Minerve class submarine]] +One of the astronomers selected for the search was [[Giuseppe Piazzi]] at the Academy of [[Palermo]], Sicily. Before receiving his invitation to join the group, Piazzi discovered Ceres on 1 January 1801.<ref>{{cite book |first=Michael |last=Hoskin |year=1999 |title=The Cambridge Concise History of Astronomy |publisher=Cambridge University press |isbn=978-0-521-57600-0 |pages=160–161 }}</ref> He was searching for "the 87th [star] of the Catalogue of the Zodiacal stars of [[Nicolas Louis de Lacaille|Mr la Caille]]", but found that "it was preceded by another".<ref name="hoskin">{{cite web |last=Hoskin |first=Michael |date=26 June 1992 |url=http://www.astropa.unipa.it/HISTORY/hoskin.html |title=Bode's Law and the Discovery of Ceres |publisher=Observatorio Astronomico di Palermo "Giuseppe S. Vaiana" |accessdate=5 July 2007 |archiveurl=http://www.webcitation.org/5msUt6uRh |archivedate=18 January 2010 |deadurl=no }}</ref> Instead of a star, Piazzi had found a moving star-like object, which he first thought was a [[comet]].<ref name="Forbes1971">{{cite journal |last=Forbes |first=Eric G. |title=Gauss and the Discovery of Ceres |journal=Journal for the History of Astronomy |volume=2 |pages=195–199 |year=1971 |bibcode=1971JHA.....2..195F }}</ref> Piazzi observed Ceres a total of 24 times, the final time on 11 February 1801, when illness interrupted his observations. He announced his discovery on 24 January 1801 in letters to only two fellow astronomers, his compatriot [[Barnaba Oriani]] of [[Milan]] and Bode of [[Berlin]].<ref>{{cite book |author=Clifford J. Cunningham |title=The first asteroid: Ceres, 1801–2001 |url=http://books.google.com/books?id=CXdMPwAACAAJ |year=2001 |publisher=Star Lab Press |isbn=978-0-9708162-1-4 }}</ref> He reported it as a comet but "since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet".<ref name="hoskin" /> In April, Piazzi sent his complete observations to Oriani, Bode, and [[Jérôme Lalande]] in Paris. The information was published in the September 1801 issue of the ''Monatliche Correspondenz''.<ref name="Forbes1971" /> -== Arts, entertainment, and media == -===Anime and manga=== -* ''[[Ceres, Celestial Legend]]'' (''Ayashi no Ceres''), an anime/manga work -===Fictional entities=== -* Ceres Space Colony, from the video game ''[[Super Metroid]]'' -* Geoffrey Fourmyle of Ceres, one of the identities of Gulliver Foyle, in the Alfred Bester book ''[[The Stars My Destination]]'' -* The Ceres Ocean, in the alternate Earth of the ''[[Ace Combat]]'' video game series -* [[Sailor Ceres]], a.k.a. CereCere, a character in ''Sailor Moon'' -* [[Seras Victoria]], a character in the anime/manga ''Hellsing'', of which an alternate romanization is "Ceres" -===Literature=== -* ''[[Ceres Storm]]'' (2000), a science fiction novel by American author David Herter -===Music=== -* ''Ceres'' (2005), an orchestral work by [[Mark-Anthony Turnage]] +By this time, the apparent position of Ceres had changed (mostly due to Earth's orbital motion), and was too close to the Sun's glare for other astronomers to confirm Piazzi's observations. Toward the end of the year, Ceres should have been visible again, but after such a long time it was difficult to predict its exact position. To recover Ceres, [[Carl Friedrich Gauss]], then 24 years old, developed an [[Gauss' Method|efficient method]] of [[orbit determination]].<ref name="Forbes1971" /> In only a few weeks, he predicted the path of Ceres and sent his results to von Zach. On 31 December 1801, von Zach and [[Heinrich Wilhelm Matthäus Olbers|Heinrich W. M. Olbers]] found Ceres near the predicted position and thus recovered it.<ref name="Forbes1971" /> -== Brands and enterprises == -* [[Ceres (organization)]], a coalition of investors and environmentalists (formerly the Coalition for Environmentally Responsible Economies) -* [[Ceres Brewery]], a brewery in Aarhus, Denmark -* [[Ceres Fruit Juices]], the South African juice company -* [[Ceres Hellenic Shipping Enterprises]], a Greek shipping company -* [[Ceres, Inc.]], a US energy crop seeds developer -* [[Ceres Liner]], a bus company in the Philippines -* [[Ceres Power]], a UK company developing small-scale [[solid oxide fuel cell]]s +The early observers were only able to calculate the size of Ceres to within an [[order of magnitude]]. Herschel underestimated its diameter as 260&nbsp;km in 1802, whereas in 1811 [[Johann Hieronymus Schröter]] overestimated it as 2,613&nbsp;km.<ref>{{cite web |last=Hilton |first=James L |authorlink=James L. Hilton |title=Asteroid Masses and Densities |work=U.S. Naval Observatory |url=http://www.lpi.usra.edu/books/AsteroidsIII/pdf/3008.pdf |accessdate=23 June 2008 |format=PDF }}</ref><ref name="Hughes1994">{{cite journal |last=Hughes |first=D. W. |title=The Historical Unravelling of the Diameters of the First Four Asteroids |journal=R.A.S. Quarterly Journal |volume=35 |issue=3 |page=331 |year=1994 |bibcode=1994QJRAS..35..331H}}[http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1994QJRAS..35..331H&defaultprint=YES&page_ind=4&filetype=.pdf (Page 335)]</ref> -==Education== -* [[Ceres Connection]], a cooperative program between MIT's Lincoln Laboratory and the Society for Science and the Public dedicated for promoting science education -* [[Ceres School]], an historic school building located at Ceres in Allegany County, New York +===Name=== +Piazzi originally suggested the name ''Cerere Ferdinandea'' for his discovery, after the goddess [[Ceres (Roman mythology)|Ceres]] ([[Roman mythology|Roman goddess]] of agriculture, ''Cerere'' in Italian, who was believed to have originated in Sicily and whose oldest temple was there) and [[Ferdinand I of the Two Sicilies|King Ferdinand]] of [[Kingdom of Sicily|Sicily]].<ref name="hoskin" /><ref name="Forbes1971" /> "Ferdinandea", however, was not acceptable to other nations and was dropped. +Ceres was called ''[[Hera]]'' for a short time in Germany.<ref>{{cite book |author=Foderà Serio, G.; Manara, A.; Sicoli, P. |editor=W. F. Bottke Jr., A. Cellino, P. Paolicchi, and R. P. Binzel |year=2002 |chapter=Giuseppe Piazzi and the Discovery of Ceres |title=Asteroids III |publisher=University of Arizona Press |pages=17–24 |location=Tucson, Arizona |url=http://www.lpi.usra.edu/books/AsteroidsIII/pdf/3027.pdf |format=PDF |accessdate=25 June 2009 }}</ref> +In Greece, it is called [[Demeter]] (''Δήμητρα''), after the Greek equivalent of the Roman ''Cerēs'';<ref group="lower-alpha">All other languages but one use a variant of ''Ceres/Cerere'': Russian ''Tserera'', Persian ''Seres'', Japanese ''Keresu''. The exception is Chinese, which uses 'grain-god(dess) star' (穀神星 ''gǔshénxīng''). Note that this is unlike the goddess Ceres, where Chinese does use the Latin name (刻瑞斯 ''kèruìsī'').</ref> in English, that name is used for the asteroid [[1108 Demeter]]. -==Sport== -* [[Ceres F.C.]], a Philippine football team -* [[Ceres Futebol Clube]], a Brazilian football team from the city of Rio de Janeiro +The regular adjectival forms of the name are ''Cererian'' and ''Cererean'',<ref>{{cite book |author=Rüpke, Jörg |authorlink=Jörg Rüpke |title=A Companion to Roman Religion |url=http://books.google.com/books?id=FRRLOltuxDcC&pg=PT90 |year=2011 |publisher=John Wiley and Sons |isbn=978-1-4443-4131-7 |pages=90– }}</ref> derived from the [[Latin]] [[genitive]] ''Cereris'',<ref name="Simpson1979" /> but ''Ceresian'' is occasionally seen for the goddess (as in the sickle-shaped [[Ceresian Lake]]), as is the shorter form ''Cerean''. -== Other uses == -* [[Ceres (workstation)]], a computer workstation built at ETH Zürich -* [[Ceres series (disambiguation)]], several series of postage stamps representing the goddess Ceres +The old [[Astronomical symbols|astronomical symbol]] of Ceres is a [[sickle]], {{angbr|{{unicode|⚳}}}} ([[File:Ceres symbol.svg|18px|Sickle variant symbol of Ceres]]),<ref>Unicode value U+26B3</ref> similar to [[Venus]]'s symbol {{angbr|{{huge|{{Unicode|♀}}|170%|valign=normal}}}} but with a break in the circle. It has a variant {{angbr| [[File:Ceres2.svg|8px|Cee variant symbol of Ceres]] }}, reversed under the influence of the initial letter 'C' of 'Ceres'. These were later replaced with the generic asteroid symbol of a numbered disk, {{angbr|①}}.<ref name="Forbes1971" /><ref>{{cite journal |last=Gould |first=B. A. |authorlink=Benjamin Apthorp Gould |title=On the symbolic notation of the asteroids |journal=Astronomical Journal |year=1852 |volume=2 |issue=34 |page=80 |bibcode=1852AJ......2...80G |doi=10.1086/100212 }}</ref> -== See also == -* [[Cereal]] +[[Cerium]], a [[rare-earth element]] discovered in 1803, was named after Ceres.<ref>{{cite web |url=http://www.webelements.com/cerium/history.html |title=Cerium: historical information |publisher=Adaptive Optics |accessdate=27 April 2007 }}</ref>{{refn|In 1807 Klaproth tried to change the name to the more etymologically justified "cererium", but it did not catch on.<ref>{{OED|Cerium }}</ref> |group = "lower-alpha"}} In the same year another element was also initially named after Ceres, but when cerium was named, its discoverer changed the name to [[palladium]], after the second asteroid, [[2 Pallas]].<ref>{{cite web |url=http://alchemy.chem.uwm.edu/amalgamator/features/feat2003/features.html#yag |date=30 October 2003 |title=Amalgamator Features 2003: 200 Years Ago |accessdate=21 August 2006 |archiveurl=https://web.archive.org/web/20060207121906/http://alchemy.chem.uwm.edu/amalgamator/features/feat2003/features.html |archivedate=7 February 2006 }}</ref> + +===Classification=== +The categorization of Ceres has changed more than once and has been the subject of some disagreement. [[Johann Elert Bode]] believed Ceres to be the "missing planet" he had proposed to exist between [[Mars]] and [[Jupiter]], at a distance of 419&nbsp;million&nbsp;km (2.8&nbsp;[[Astronomical unit|AU]]) from the Sun.<ref name="hoskin" /> Ceres was assigned a planetary symbol, and [[Planet#former planets|remained listed as a planet]] in astronomy books and tables (along with [[2 Pallas]], [[3 Juno]], and [[4 Vesta]]) for half a century.<ref name="hoskin" /><ref name="Forbes1971" /><ref name="Hilton" /> +[[File:Moon and Asteroids 1 to 10.svg|thumb|left|Sizes of the first ten main-belt objects discovered profiled against the [[Moon]]. Ceres is far left (1).]] +As other objects were discovered in the neighborhood of Ceres, it was realized that Ceres represented the first of a new class of objects.<ref name="hoskin" /> In 1802, with the discovery of 2 Pallas, [[William Herschel]] coined the term ''asteroid'' ("star-like") for these bodies,<ref name="Hilton">{{cite web |url=http://aa.usno.navy.mil/faq/docs/minorplanets.php |first=James L. |last=Hilton |title=When Did the Asteroids Become Minor Planets? |date=17 September 2001 |accessdate=16 August 2006 |archiveurl=http://www.webcitation.org/5msUtFmJu |archivedate=18 January 2010 |deadurl=no }}</ref> writing that "they resemble small stars so much as hardly to be distinguished from them, even by very good telescopes".<ref>{{cite web |url=http://links.jstor.org/sici?sici=0261-0523%281802%2992%3C213%3AOOTTLD%3E2.0.CO%3B2-R |first=William |last=Herschel |authorlink=William Herschel |title=''Observations on the two lately discovered celestial Bodies.'' |date=6 May 1802 |archiveurl=http://www.webcitation.org/62D5ZCrRO |archivedate=5 October 2011 |deadurl=no }}</ref> As the first such body to be discovered, Ceres was given the designation 1 Ceres under the modern system of [[minor-planet designation]]s. By the 1860s, the existence of a fundamental difference between asteroids such as Ceres and the major planets was widely accepted, though a precise definition of "planet" was never formulated.<ref name="Hilton" /> +{{Multiple image + | direction = vertical + | width = 150 + | image1 = Ceres, Earth & Moon size comparison.jpg + | alt1 = Ceres (bottom left), the Moon and Earth, shown to scale + | caption1 = Ceres (bottom left), the [[Moon]] and Earth, shown to scale + | image2 = Eros, Vesta and Ceres size comparison.jpg + | alt2 = Size comparison of Vesta, Ceres and Eros + | caption2 = Size comparison of [[4 Vesta|Vesta]], Ceres and [[433 Eros|Eros]] +}} +The 2006 debate surrounding [[Pluto]] and what constitutes a planet led to Ceres being considered for reclassification as a planet.<ref>{{cite web |last=Battersby |first=Stephen |date=16 August 2006 |url=http://space.newscientist.com/article/dn9762 |title=Planet debate: Proposed new definitions |publisher=New Scientist |accessdate=27 April 2007 |archiveurl=http://www.webcitation.org/62D6CF1Zj |archivedate=5 October 2011 |deadurl=no }}</ref><ref>{{cite news |first=Steve |last=Connor |title=Solar system to welcome three new planets |publisher=NZ Herald |date=16 August 2006 |url=http://www.nzherald.co.nz/section/story.cfm?c_id=5&ObjectID=10396493 |accessdate=27 April 2007 |archiveurl=http://www.webcitation.org/62D6CSjoX |archivedate=5 October 2011 |deadurl=no }}</ref> A proposal before the [[International Astronomical Union]] for the [[definition of planet|definition of a planet]] would have defined a planet as "a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid-body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet".<ref>{{cite web |authorlink=Owen Gingerich |last1=Gingerich |first1=Owen |date=16 August 2006 |url=http://www.iau.org/iau0601.424.0.html |title=The IAU draft definition of "Planet" and "Plutons" |publisher=IAU |accessdate=27 April 2007 |archiveurl=http://www.webcitation.org/62D6DNhLH |archivedate=5 October 2011 |deadurl=no |display-authors=etal}}</ref> Had this resolution been adopted, it would have made Ceres the fifth planet in order from the Sun.<ref>{{cite web |date=16 August 2006 |url=http://www.spacedaily.com/reports/The_IAU_Draft_Definition_Of_Planets_And_Plutons_999.html |title=The IAU Draft Definition of Planets And Plutons |publisher=SpaceDaily |accessdate=27 April 2007 |archiveurl=http://www.webcitation.org/5msUtP4zI |archivedate=18 January 2010 |deadurl=no }}</ref> This never happened, however, and on 24 August 2006 a modified definition was adopted, carrying the additional requirement that a planet must have "[[clearing the neighbourhood|cleared the neighborhood]] around its orbit". By this definition, Ceres is not a planet because it does not dominate its orbit, sharing it as it does with the thousands of other asteroids in the [[asteroid belt]] and constituting only about a third of the mass of the belt. Bodies that met the first proposed definition but not the second, such as Ceres, were instead classified as [[dwarf planet]]s. + +Ceres is the largest object in the asteroid belt.<ref name="Rivkin2006" /> +It is sometimes assumed that Ceres has been ''re''classified as a dwarf planet, and that it is therefore no longer considered an asteroid. For example, a news update at Space.com spoke of "Pallas, the largest asteroid, and Ceres, the dwarf planet formerly classified as an asteroid",<ref>Geoff Gaherty, "How to Spot Giant Asteroid Vesta in Night Sky This Week", 3 August 2011 [http://www.space.com/12537-asteroid-vesta-skywatching-tips.html How to Spot Giant Asteroid Vesta in Night Sky This Week | Asteroid Vesta Skywatching Tips | Amateur Astronomy, Asteroids & Comets | Space.com] {{WebCite |url=http://www.webcitation.org/62D6DYR28 |date=5 October 2011 }}</ref> whereas an IAU question-and-answer posting states, "Ceres is (or now we can say it was) the largest asteroid", though it then speaks of "other asteroids" crossing Ceres's path and otherwise implies that Ceres is still considered an asteroid.<ref name="IAU-QA">{{cite web |url=http://www.iau.org/Q_A2.415.0.html |title=Question and answers 2 |publisher=IAU |accessdate=31 January 2008 |archiveurl=http://www.webcitation.org/62D6FRw3H |archivedate=5 October 2011 |deadurl=no }}</ref> The [[Minor Planet Center]] notes that such bodies may have dual designations.<ref>{{cite web |url=http://cfa-www.harvard.edu/mpec/K06/K06R19.html |title=MPEC 2006-R19: EDITORIAL NOTICE |last1=Spahr |first1=T. B. |authorlink=Timothy B. Spahr |publisher=Minor Planet Center |date=7 September 2006 |quote=the numbering of "dwarf planets" does not preclude their having dual designations in possible separate catalogues of such bodies. |accessdate=31 January 2008 |archiveurl=http://www.webcitation.org/62D6FtCBi |archivedate=5 October 2011 |deadurl=no }}</ref> The 2006 IAU decision that classified Ceres as a dwarf planet never addressed whether it is or is not an asteroid. Indeed, the IAU has never defined the word 'asteroid' at all, having preferred the term '[[minor planet]]' until 2006, and preferring the terms '[[small Solar System body]]' and 'dwarf planet' after 2006. Lang (2011) comments "the [IAU has] added a new designation to Ceres, classifying it as a dwarf planet.&nbsp;... By [its] definition, [[Eris (dwarf planet)|Eris]], [[Haumea]], [[Makemake]] and [[Pluto]], as well as the largest asteroid, 1 Ceres, are all dwarf planets", and describes it elsewhere as "the dwarf planet–asteroid 1 Ceres".<ref>{{cite book |last=Lang |first=Kenneth |title=The Cambridge Guide to the Solar System |publisher=Cambridge University Press |year=2011 |pages=372, 442 |url=https://books.google.nl/books?hl=nl&lr=&id=S4xDhVCxAQIC&oi=fnd&pg=PR5&dq=The+Cambridge+Guide+to+the+Solar+System&ots=LDL46w6zaq&sig=yVwId0vJCYWv-2xmwQEdKaaMbsY#v=onepage&q=The%20Cambridge%20Guide%20to%20the%20Solar%20System&f=false}}</ref> NASA continues to refer to Ceres as an asteroid,<ref>[http://www.ustream.tv/recorded/16375687/highlight/191666 NASA/JPL, ''Dawn Views Vesta'', 2 August 2011] {{WebCite |url=http://www.webcitation.org/62D6G0qTd |date=5 October 2011}} ("''Dawn'' will orbit two of the largest asteroids in the Main Belt").</ref> as do various academic textbooks.<ref>{{cite book |last=de Pater |last2=Lissauer |year=2010 |title=Planetary Sciences |edition=2nd |publisher=Cambridge University Press |isbn=978-0-521-85371-2 }}</ref><ref>{{cite book |last=Mann |last2=Nakamura |last3=Mukai |year=2009 |title=Small bodies in planetary systems |series=Lecture Notes in Physics |volume=758 |publisher=Springer-Verlag |isbn=978-3-540-76934-7 }}</ref> + +==Physical characteristics== +Ceres has a mass of {{val|9.39|e=20|u=kg}} as determined from the ''Dawn'' spacecraft.<ref name="Rayman20150528">{{cite web |title=Dawn Journal, May 28, 2015 |last=Rayman |first=Marc D. |publisher=[[Jet Propulsion Laboratory]] |url=http://dawnblog.jpl.nasa.gov/2015/05/28/dawn-journal-may-28-2015/ |date=28 May 2015 |accessdate=29 May 2015}}</ref> With this mass Ceres comprises approximately a third of the estimated total 3.0&nbsp;±&nbsp;0.2{{e|21}}&nbsp;kg mass of the asteroid belt,<ref name="Pitjeva2005">{{cite journal |last=Pitjeva |first=E. V. |authorlink=Elena V. Pitjeva |title=High-Precision Ephemerides of Planets—EPM and Determination of Some Astronomical Constants |journal=Solar System Research |year=2005 |volume=39 |issue=3 |page=176 |doi=10.1007/s11208-005-0033-2 |bibcode=2005SoSyR..39..176P}}</ref> which is in turn approximately 4% of the mass of the [[Moon]]. The mass of Ceres is large enough to give it a nearly spherical shape in [[hydrostatic equilibrium]].<ref name="Thomas2005" /> Among Solar System bodies, Ceres is intermediate in size between the smaller [[90482 Orcus|Orcus]] and {{mpl-|307261|2002 MS|4}} and the larger [[Tethys (moon)|Tethys]]. Its surface area is approximately the same as the land area of [[India]] or [[Argentina]].<ref>Approximately forty percent that of Australia, a third the size of the US or Canada, 12× that of the UK</ref> + +===Internal structure=== +[[File:Ceres Cutaway.jpg|left|thumb|250px|Diagram showing a possible internal structure of Ceres]] +Ceres's [[oblateness]] is consistent with a differentiated body, a rocky core overlain with an icy [[Mantle (geology)|mantle]].<ref name="Thomas2005">{{cite journal |first1=P. C. |last1=Thomas |author2=Parker, J. Wm.; McFadden, L. A. |title=Differentiation of the asteroid Ceres as revealed by its shape |year=2005 |journal=Nature |volume=437 |pages=224–226 |doi=10.1038/nature03938 |bibcode=2005Natur.437..224T |pmid=16148926 |issue=7056 |display-authors=etal}}</ref> This 100-kilometer-thick mantle (23%–28% of Ceres by mass; 50% by [[volume (unit)|volume]])<ref>0.72–0.77 anhydrous rock by mass, per William B. McKinnon (2008) [http://adsabs.harvard.edu/abs/2008DPS....40.3803M "On The Possibility Of Large KBOs Being Injected Into The Outer Asteroid Belt"]. ''American Astronomical Society,'' DPS meeting No. 40, #38.03 {{WebCite |url=http://www.webcitation.org/62D6Hmyrx |date=5 October 2011 }}</ref> contains up to 200&nbsp;million cubic kilometers of water, which would be more than the amount of [[fresh water]] on [[Earth]].<ref name="Carey2006">{{cite news |url=http://space.com/scienceastronomy/050907_ceres_planet.html |title=Largest Asteroid Might Contain More Fresh Water than Earth |first=Bjorn |last=Carey |publisher=SPACE.com |date=7 September 2005 |accessdate=16 August 2006 |archiveurl=http://www.webcitation.org/62D6ITs0O |archivedate=5 October 2011 |deadurl=no }}</ref> This result is supported by the observations made by the Keck telescope in 2002 and by evolutionary modeling.<ref name="McCord2005">{{cite journal |last=McCord |first=Thomas B. |title=Ceres: Evolution and current state |journal=Journal of Geophysical Research |volume=110 |issue=E5 |page=E05009 |year=2005 |doi=10.1029/2004JE002244 |bibcode=2005JGRE..11005009M }}</ref><ref name="Carry2008" /> Also, some characteristics of its surface and history (such as its distance from the Sun, which weakened solar radiation enough to allow some fairly low-freezing-point components to be incorporated during its formation), point to the presence of [[volatiles|volatile materials]] in the interior of Ceres.<ref name="Carry2008" /> It has been suggested that a remnant layer of liquid water may have survived to the present under a layer of ice.<ref name = "McCord2005"/><ref name = "O'Brien2015"/> + +Alternatively, the shape and dimensions of Ceres may be explained by an interior that is porous and either partially differentiated or completely undifferentiated. The presence of a layer of rock on top of ice would be gravitationally unstable. If any of the rock deposits sank into a layer of differentiated ice, salt deposits would be formed. Such deposits have not been detected. Thus it is possible that Ceres does not contain a large ice shell, but was instead formed from low-density asteroids with an aqueous component. The decay of radioactive isotopes may not have produced sufficient heat to cause differentiation.<ref>{{cite journal |last=Zolotov |first=M. Yu. |year=2009 |pages=183–193 |issue=1 |title=On the Composition and Differentiation of Ceres |volume=204 |journal=Icarus |doi=10.1016/j.icarus.2009.06.011 |bibcode=2009Icar..204..183Z }}</ref> + +===Surface=== +{{main|List of geological features on Ceres}} +The surface composition of Ceres is broadly similar to that of [[C-type asteroid]]s.<ref name="Rivkin2006" /> Some differences do exist. The ubiquitous features in Ceres's [[Infrared|IR]] [[spectrum]] are those of hydrated materials, which indicate the presence of significant amounts of water in its interior. Other possible surface constituents include iron-rich clay minerals ([[cronstedtite]]) and [[carbonate minerals]] ([[dolomite]] and [[siderite]]), which are common minerals in [[carbonaceous chondrite]] meteorites.<ref name="Rivkin2006" /> The spectral features of carbonates and clay minerals are usually absent in the spectra of other C-type asteroids.<ref name="Rivkin2006">{{cite journal |last1=Rivkin |first1=A. S. |author2=Volquardsen, E. L.; Clark, B. E. |title=The surface composition of Ceres:Discovery of carbonates and iron-rich clays |journal=Icarus |volume=185 |issue=2 |pages=563–567 |year=2006 |doi=10.1016/j.icarus.2006.08.022 |url=http://irtfweb.ifa.hawaii.edu/~elv/icarus185.563.pdf |format=PDF |accessdate=8 December 2007 |bibcode=2006Icar..185..563R }}</ref> Sometimes Ceres is classified as a [[G-type asteroid]].<ref name="Parker2002" /> + +The Cererian surface is relatively warm. The maximum temperature with the [[Sun]] overhead was estimated from measurements to be 235&nbsp;[[kelvin|K]] (approximately −38&nbsp;°C, −36&nbsp;°F) on 5 May 1991.<ref name="Saint-Pe1993">{{cite journal |last1=Saint-Pé |first1=O. |author2=Combes, N.; Rigaut F. |title=Ceres surface properties by high-resolution imaging from Earth |year=1993 |volume=105 |issue=2 |pages=271–281 |journal=Icarus |doi=10.1006/icar.1993.1125 |bibcode=1993Icar..105..271S }}</ref> Ice is unstable at this temperature. Material left behind by the sublimation of surface ice could explain the dark surface of Ceres compared to the icy moons of the outer Solar System. +[[File:PIA19571-Ceres-DwarfPlanet-Dawn-VIR-Image-20150516.jpg|thumb|250px|center|<center>[[Infrared spectroscopy|VIR spectrometer]] mapping<br>(bw; true-color; IR) of Ceres.</center>]] + +====Observations prior to ''Dawn''==== +[[File:Ceres Rotation.jpg|thumb|[[Hubble Space Telescope|HST]] images taken over a span of 2 hours and 20 minutes in 2004]] +Prior to the ''Dawn'' mission, only a few surface features had been unambiguously detected on Ceres. High-resolution [[ultraviolet]] [[Hubble Space Telescope]] images taken in 1995 showed a dark spot on its surface, which was nicknamed "Piazzi" in honor of the discoverer of Ceres.<ref name="Parker2002" /> This was thought to be a crater. Later [[near-infrared]] images with a higher resolution taken over a whole rotation with the [[Keck telescope]] using [[adaptive optics]] showed several bright and dark features moving with Ceres's rotation.<ref name="Carry2008" /><ref name="Keck" /> Two dark features had circular shapes and are presumably craters; one of them was observed to have a bright central region, whereas another was identified as the "Piazzi" feature.<ref name="Carry2008">{{cite journal |first1=Benoit |last1=Carry |title=Near-Infrared Mapping and Physical Properties of the Dwarf-Planet Ceres |year=2007 |journal=Astronomy & Astrophysics |volume=478 |issue=1 |pages=235–244 |url=https://web.archive.org/web/20080530130946/http://www2.keck.hawaii.edu/inst/people/conrad/nsfGrantRef/2007-arXiv-Benoit.Carry.pdf |format=PDF |doi=10.1051/0004-6361:20078166 |bibcode=2008A&A...478..235C |arxiv=0711.1152 |display-authors=etal}}</ref><ref name="Keck" /> Visible-light [[Hubble Space Telescope]] images of a full rotation taken in 2003 and 2004 showed 11 recognizable surface features, the natures of which are yet undetermined.<ref name="Li2006">{{cite journal |last1=Li |first1=Jian-Yang |author2=McFadden, Lucy A.; Parker, Joel Wm. |title=Photometric analysis of 1 Ceres and surface mapping from HST observations |journal=Icarus |volume=182 |issue=1 |pages=143–160 |year=2006 |doi=10.1016/j.icarus.2005.12.012 |url=http://www.sciencedirect.com/science/article/pii/S0019103506000054 |accessdate=8 December 2007 |bibcode=2006Icar..182..143L }}</ref><ref name="Hubbl12003-4">{{cite news |url=http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/27/ |title=Largest Asteroid May Be 'Mini Planet' with Water Ice |date=7 September 2005 |accessdate=16 August 2006 |publisher=HubbleSite |archiveurl=http://www.webcitation.org/62D6IzDMj |archivedate=5 October 2011 |deadurl=no }}</ref> One of these features corresponds to the "Piazzi" feature observed earlier.<ref name="Li2006" /> + +These last observations also determined that the north pole of Ceres points in the direction of [[right ascension]] 19&nbsp;h 24&nbsp;min (291°), [[declination]] +59°, in the [[constellation]] [[Draco (constellation)|Draco]]. This means that Ceres's [[axial tilt]] is very small—approximately 3°.<ref name="Thomas2005" /><ref name="Li2006" /> ''Dawn'' would later determine that the axis points in a different direction. + +====Observations by ''Dawn''==== +{{see also|Bright spots on Ceres|Pyramid-shaped mountain on Ceres}} +''Dawn'' revealed a large number of craters with low relief, indicating that they lie over a relatively soft surface, probably of water ice. One crater, with extremely low relief, is {{convert|270|km|mi|abbr=on}} in diameter,<ref name="planetary.org"/> reminiscent of large, flat craters on [[Tethys (moon)|Tethys]] and [[Iapetus (moon)|Iapetus]]. An unexpectely large number of Cererian craters have central pits.<ref>[http://www.jpl.nasa.gov/news/news.php?release=2015-215]</ref> Several [[Bright spots on Ceres|bright spots]] have been observed by ''Dawn'', the brightest spot ("Spot 5") located in the middle of an {{convert|80|km|mi|abbr=on}} crater called [[Occator (crater)|Occator]].<ref>{{cite web |title=USGS: Ceres nomenclature |url=http://planetarynames.wr.usgs.gov/images/ceres.pdf |accessdate=16 July 2015 }}</ref> From images taken of Ceres on 4 May 2015, the secondary bright spot was revealed to actually be a group of scattered bright areas, possibly as many as 10. These bright features have an albedo of approximately 40%<ref name=siliconvalleyastrolecture>{{cite speech + |title=Now Appearing At a Dwarf Planet Near You: NASA's Dawn Mission to the Asteroid Belt + |first=Marc + |last=Rayman + |author-link= + |event=Silicon Valley Astronomy Lectures + |location=Foothill College, Los Altos, CA + |date=8 April 2015 + |url= + |access-date= +}}</ref> that are caused by a substance on the surface, possibly ice or salts, reflecting sunlight.<ref>{{Cite web|last=Landau |first=Elizabeth |title=Ceres Animation Showcases Bright Spots |url=http://www.jpl.nasa.gov/news/news.php?feature=4582 |date=11 May 2015 |work=[[NASA]] |accessdate=13 May 2015 }}</ref><ref name="Witze2015">{{cite news |last=Witze |first=Alexandra |url=http://www.nature.com/news/mystery-haze-appears-above-ceres-s-bright-spots-1.18032 |title=Mystery haze appears above Ceres’s bright spots |work=Nature News |date=21 July 2015 |accessdate=2015-07-23 }}</ref> A haze periodically appears above Spot 5, the best known bright spot, supporting the hypothesis that some sort of outgassing or sublimating ice formed the bright spots.<ref name="Witze2015"/><ref>http://www.planetary.org/blogs/guest-blogs/2015/0721-dawn-at-ceres-a-haze-in-occator-rivkin.html</ref> + +{| class="wikitable" style="margin:0.5em auto; width:600px;" +! Ceres - dwarf planet +|- +| style="font-size:88%" |[[File:PIA19316-Ceres-DwarfPlanet-DawnMission-VIR-20150413.jpg|600px]] +<center>[[Bright spots on Ceres]] in visible and infrared:<br>"Spot 1" (top row) ("cooler" than surroundings);<br>"Spot 5" (bottom) ("similar in temperature" as surroundings) (April 2015)</center> +|} + +{{multiple image|center|caption_align=center|header_align=center|align=center|header= |width= +|image1=Occator crater.jpg|width1=200 +|caption1=<center>[[Bright spots on Ceres|Bright "Spot 5"]] imaged by ''Dawn'' <br>from {{convert|4400|km|mi|abbr=on}} on 6 June 2015.</center> +|image2=PIA19606-Ceres-Dawn-GlobalMap-OccatorCrater-BrightSpot5-20150728.jpg|width2=200 +|caption2=<center>[[Bright spots on Ceres|Bright "Spot 5"]] in [[Occator (crater)|Occator crater]]<br>Elevations (red=high; blue=low)<br>(28 July 2015)<ref name="NASA-20150728-el">{{cite web |last=Landau |first=Elizabeth |title=New Names and Insights at Ceres |url=http://www.jpl.nasa.gov/news/news.php?feature=4669 |date=28 July 2015 |work=[[NASA]] |accessdate=28 July 2015 }}</ref></center> +|image3=PIA19606-Ceres-Dawn-GlobalMap-MtnCrop-20150728.jpg|width3=203 +|caption3=<center>"[[Pyramid-shaped mountain on Ceres|Pyramid-shaped mountain]]"<br>Elevations (red=high; blue=low)<br>(28 July 2015)</center> +|image4=PIA19574-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image6-20150606-crop100.jpg|width4=200 +|caption4=<center>"[[Pyramid-shaped mountain on Ceres|Pyramid-shaped mountain]]", estimated to be approximately {{convert|5|km|mi ft|abbr=on}} high.<ref name="NASA-20150606-19574">{{cite web |author=Staff |title=PIA19574: Dawn Survey Orbit Image 6 |url=http://photojournal.jpl.nasa.gov/catalog/PIA19574 |date=17 June 2016 |work=[[NASA]] |accessdate=20 June 2015 }}</ref> Imaged by ''Dawn'' from {{convert|4400|km|mi|abbr=on}} on 6 June 2015.</center> +}} +<!--- +{{Double image|center|Occator crater.jpg|400|PIA19574-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image6-20150606-crop100.jpg|400|<center>[[Bright spots on Ceres|Bright "Spot 5"]] imaged by ''Dawn'' <br>from {{convert|4400|km|mi|abbr=on}} on 6 June 2015.</center>|<center>"[[Pyramid-shaped mountain on Ceres|Pyramid-shaped mountain]]", estimated to be approximately {{convert|5|km|mi ft|abbr=on}} high.<ref name="NASA-20150606-19574">{{cite web |author=Staff |title=PIA19574: Dawn Survey Orbit Image 6 |url=http://photojournal.jpl.nasa.gov/catalog/PIA19574 |date=17 June 2016 |work=[[NASA]] |accessdate=20 June 2015 }}</ref> Imaged by ''Dawn'' from {{convert|4400|km|mi|abbr=on}} on 6 June 2015.</center>}}---> + +===Atmosphere=== +There are indications that Ceres may have a tenuous water vapor [[Celestial body atmosphere|atmosphere]] outgassing from water ice on the surface.<ref name="Ahearn1992">{{cite journal |last1=A'Hearn |first1=Michael F. |author2=Feldman, Paul D. |title=Water vaporization on Ceres |journal=Icarus |volume=98 |issue=1 |pages=54–60 |year=1992 |doi=10.1016/0019-1035(92)90206-M |bibcode=1992Icar...98...54A }}</ref><ref>[http://www.space.com/22891-ceres-dwarf-planet.html Ceres: The Smallest and Closest Dwarf Planet]. ''Space.com'' 22 January 2014</ref><ref>[http://www.nasa.gov/jpl/herschel/dwarf-planet-ceres-pia17830 Dwarf Planet Ceres, Artist's Impression]. 21 January 2014. NASA</ref> + +Surface water ice is unstable at distances less than 5 AU from the Sun,<ref name="Jewitt2007">{{cite book |year=2007 |title=Protostars and Planets V |publisher=University of Arizona Press |chapter=Water in the Small Bodies of the Solar System |pages=863–878 |isbn=0-8165-2654-0 |editors=Reipurth, B.; Jewitt, D.; Keil, K. |url=http://www.ifa.hawaii.edu/~meech/a740/2006/spring/papers/PPV2006.pdf |format=PDF |author=Jewitt, D; Chizmadia, L.; Grimm, R.; Prialnik, D }}</ref> so it is expected to [[Sublimation (chemistry)|sublime]] if it is exposed directly to solar radiation. Water ice can migrate from the deep layers of Ceres to the surface, but escapes in a very short time. As a result, it is difficult to detect water vaporization. Water escaping from polar regions of Ceres was possibly observed in the early 1990s but this has not been unambiguously demonstrated. It may be possible to detect escaping water from the surroundings of a fresh impact crater or from cracks in the subsurface layers of Ceres.<ref name="Carry2008" /> [[Ultraviolet]] observations by the [[IUE]] spacecraft detected statistically significant amounts of [[hydroxide]] ions near Ceres' north pole, which is a product of water vapor dissociation by ultraviolet solar radiation.<ref name="Ahearn1992" /> + +In early 2014, using data from the [[Herschel Space Observatory]], it was discovered that there are several localized (not more than 60&nbsp;km in diameter) mid-latitude sources of water vapor on Ceres, which each give off approximately {{val|e=26}} molecules (or 3&nbsp;kg) of water per second.<ref name="Kuppers2014">{{cite journal |last1=Küppers |first1=M. |last2=O'Rourke |first2=L. |last3=Bockelée-Morvan |first3=D. |last4=Zakharov |first4=V. |last5=Lee |first5=S. |last6=Von Allmen |first6=P. |last7=Carry |first7=B. |last8=Teyssier |first8=D. |last9=Marston |first9=A. |last10=Müller |first10=T. |last11=Crovisier |first11=J. |last12=Barucci |first12=M. A. |last13=Moreno |first13=R. |title=Localized sources of water vapour on the dwarf planet (1) Ceres |journal=Nature |volume=505 |issue=7484 |date=23 January 2014 |pages=525–527 |issn=0028-0836 |doi=10.1038/nature12918 |pmid=24451541 |bibcode = 2014Natur.505..525K }}</ref><ref name="Campins2014">{{Cite doi|10.1038/505487a }}</ref>{{efn | This emission rate is modest compared to those calculated for the tidally driven plumes of [[Enceladus]] (a smaller body) and [[Europa (moon)|Europa]] (a larger body), 200&nbsp;kg/s<ref name="Hansen2006">{{Cite doi|10.1126/science.1121254 }}</ref> and 7000&nbsp;kg/s,<ref name="Europa tidal forces 2013">{{Cite doi|10.1126/science.1247051 }}</ref> respectively.}} Two potential source regions, designated Piazzi (123°E, 21°N) and Region A (231°E, 23°N), have been visualized in the near infrared as dark areas (Region A also has a bright center) by the [[W. M. Keck Observatory]]. Possible mechanisms for the vapor release are sublimation from approximately 0.6&nbsp;km² of exposed surface ice, or [[cryovolcanic]] eruptions resulting from [[Radioactive decay|radiogenic]] internal heat<ref name="Kuppers2014" /> or from pressurization of a subsurface ocean due to growth of an overlying layer of ice.<ref name = "O'Brien2015">{{cite conference + | last1 = O'Brien | first1 = D. P. | last2 = Travis | first2 = B. J. + | last3 = Feldman | first3 = W. C. | last4 = Sykes | first4 = M. V. + | last5 = Schenk | first5 = P. M. | last6 = Marchi | first6 = S. + | last7 = Russell | first7 = C. T. | last8 = Raymond | first8 = C. A. + | title = The Potential for Volcanism on Ceres due to Crustal Thickening and Pressurization of a Subsurface Ocean + | booktitle = 46th [[Lunar and Planetary Science Conference]] + | pages = 2831 | date = March 2015 | url = http://www.hou.usra.edu/meetings/lpsc2015/pdf/2831.pdf + | accessdate = 1 March 2015}}</ref> Surface sublimation would be expected to be lower when Ceres is farther from the Sun in its orbit, whereas internally powered emissions should not be affected by its orbital position. The limited data available are more consistent with cometary-style sublimation.<ref name="Kuppers2014" /> + +==Orbit== +<div style="float:right; margin:8px;"> +{| class=wikitable style="text-align:center" +|+ Proper (long-term mean) orbital elements compared to osculating (instant) orbital elements for Ceres: +!Element<br>type !![[Semi-major axis|a]]<br>(in [[Astronomical unit|AU]]) !![[Orbital eccentricity|e]] !![[Orbital Inclination|i]] !![[Orbital period|Period]]<br>(in days) +|- +|[[Proper orbital elements|Proper]]<ref name="Ceres-POE" /> ||2.7671 ||0.116198 ||9.647435 ||1681.60 +|- +|[[Osculating orbit|Osculating]]<ref name="jpl_sbdb" /><br>([[Epoch (astronomy)|Epoch]] 23 July 2010 ) ||2.7653 ||0.079138 ||10.586821 ||1679.66 +|- +|Difference ||0.0018 ||0.03706 ||0.939386 ||1.94 +|}</div> +[[File:Ceres Orbit.svg|thumb|250px|Orbit of Ceres]] +Ceres follows an orbit between Mars and Jupiter, within the [[asteroid belt]], with a period of 4.6 Earth years.<ref name="jpl_sbdb" /> The orbit is moderately inclined (''i'' = 10.6° compared to 7° for [[Mercury (planet)|Mercury]] and 17° for [[Pluto]]) and moderately [[Orbital eccentricity|eccentric]] (''e'' = 0.08 compared to 0.09 for Mars).<ref name="jpl_sbdb" /> + +The diagram illustrates the orbits of Ceres (blue) and several planets (white and gray). The segments of orbits below the ecliptic are plotted in darker colors, and the orange plus sign is the Sun's location. The top left diagram is a polar view that shows the location of Ceres in the gap between Mars and Jupiter. The top right is a close-up demonstrating the locations of the [[pericenter|perihelia]] (q) and [[apocenter|aphelia]] (Q) of Ceres and Mars. In this diagram (but not in general), the perihelion of Mars is on the opposite side of the Sun from those of Ceres and several of the large main-belt asteroids, including [[2 Pallas]] and [[10 Hygiea]]. The bottom diagram is a side view showing the inclination of the orbit of Ceres compared to the orbits of Mars and Jupiter. + +Ceres was once thought to be a member of an [[asteroid family]].<ref name="Cellino">{{cite book |author=Cellino, A. |chapter=Spectroscopic Properties of Asteroid Families |title=Asteroids III |pages=633–643 (Table on p. 636) |bibcode=2002aste.conf..633C |publisher=University of Arizona Press |year=2002 |url=http://www.lpi.usra.edu/books/AsteroidsIII/pdf/3018.pdf |format=PDF |display-authors=etal}}</ref> The asteroids of this family share similar [[proper orbital elements]], which may indicate a common origin through an asteroid collision some time in the past. Ceres was later found to have spectral properties different from other members of the family, which is now called the [[Gefion family]] after the next-lowest-numbered family member, [[1272 Gefion]].<ref name="Cellino" /> Ceres appears to be merely an interloper in the Gefion family, coincidentally having similar orbital elements but not a common origin.<ref name="Kelley">{{cite journal |author1=Kelley, M. S.; Gaffey, M. J. |title=A Genetic Study of the Ceres (Williams #67) Asteroid Family |journal=Bulletin of the American Astronomical Society |year=1996 |volume=28 |page=1097 |bibcode=1996BAAS...28R1097K }}</ref> + +The rotational period of Ceres (the Cererian day) is 9 hours and 4&nbsp;minutes.<ref name="NSSDC">{{cite journal |author=Williams, David R. |title=Asteroid Fact Sheet |year=2004 |url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/asteroidfact.html |archiveurl=http://www.webcitation.org/5msUtb6sU |archivedate=18 January 2010 |deadurl=no }}</ref> + +Ceres is in a [[Orbital resonance#Coincidental 'near' ratios of mean motion|near]]-1:1 mean-motion [[orbital resonance]] with [[2 Pallas|Pallas]] (their proper orbital periods differ by 0.2%).<ref name="Kovačević">{{cite journal |last=Kovačević |first=A. B. |title=Determination of the mass of Ceres based on the most gravitationally efficient close encounters |journal=[[Monthly Notices of the Royal Astronomical Society]] |year=2011 |volume=419 |issue=3 |pages=2725–2736 |bibcode=2012MNRAS.419.2725K |doi=10.1111/j.1365-2966.2011.19919.x |arxiv=1109.6455 }}</ref> However, a true resonance between the two would be unlikely; due to their small masses relative to their large separations, such relationships among asteroids are very rare.<ref name="Christou">{{cite journal |last=Christou |first=A. A. |title=Co-orbital objects in the main asteroid belt |journal=[[Astronomy and Astrophysics]] |volume=356 |pages=L71–L74 |year=2000 |bibcode=2000A&A...356L..71C }}</ref> Nevertheless, Ceres is able to capture other asteroids into temporary 1:1 resonant orbital relationships (for periods up to 2 million years or more); fifty such objects have been identified.<ref name="Christou2012">{{cite journal|last1=Christou|first1=A. A.|last2=Wiegert|first2=P.|title=A population of Main Belt Asteroids co-orbiting with Ceres and Vesta|journal= Icarus|volume= 217|issue= 1|date= January 2012|pages= 27–42|issn= 00191035|doi= 10.1016/j.icarus.2011.10.016|arxiv = 1110.4810 |bibcode = 2012Icar..217...27C }}</ref> + +===Transits of planets from Ceres=== +Mercury, Venus, Earth, and Mars can all appear to cross the Sun, or [[astronomical transit|transit]] it, from a vantage point on Ceres. The most common transits are those of Mercury, which usually happen every few years, most recently in 2006 and 2010. The most recent transit of Venus was in 1953, and the next will be in 2051; the corresponding dates are 1814 and 2081 for transits of Earth, and 767 and 2684 for transits of Mars.<ref>{{cite web |url=http://chemistry.unina.it/~alvitagl/solex/ |title=Solex numbers generated by Solex |accessdate=3 March 2009 |archiveurl=http://www.webcitation.org/5gOzK38bc |archivedate=29 April 2009 |deadurl=no}}</ref> + +==Origin and evolution== +Ceres is probably a surviving [[protoplanet]] (planetary embryo), which formed 4.57&nbsp;billion years ago in the [[asteroid belt]].<ref name="McCord2005" /> Although the majority of [[inner Solar System]] protoplanets (including all lunar- to Mars-sized bodies) either merged with other protoplanets to form [[terrestrial planet]]s or were ejected from the [[Solar System]] by [[Jupiter]],<ref name="Petit2001">{{cite journal |last1=Petit |first1=Jean-Marc |author2=Morbidelli, Alessandro |title=The Primordial Excitation and Clearing of the Asteroid Belt |journal=Icarus |volume=153 |issue=2 |pages=338–347 |year=2001 |doi=10.1006/icar.2001.6702 |url=http://www.gps.caltech.edu/classes/ge133/reading/asteroids.pdf |format=PDF |accessdate=25 June 2009 |bibcode=2001Icar..153..338P }}</ref> Ceres is believed to have survived relatively intact.<ref name="McCord2005" /> An alternative theory proposes that Ceres formed in the [[Kuiper belt]] and later migrated to the asteroid belt.<ref>Approximately a 10% chance of the asteroid belt acquiring a Ceres-mass KBO. William B. McKinnon, 2008, [http://adsabs.harvard.edu/abs/2008DPS....40.3803M "On The Possibility Of Large KBOs Being Injected Into The Outer Asteroid Belt"]. ''American Astronomical Society,'' DPS meeting No. 40, #38.03 {{WebCite |url=http://www.webcitation.org/62D6Hmyrx |date=5 October 2011 }}</ref> Another possible protoplanet, [[4 Vesta|Vesta]], is less than half the size of Ceres; it suffered a major impact after solidifying, losing ~1% of its mass.<ref name="Thomas1997">{{cite journal |last1=Thomas |first1=Peter C. |author2=Binzel, Richard P.; Gaffey, Michael J. |title=Impact Excavation on Asteroid 4 Vesta: Hubble Space Telescope Results |journal=Science |volume=277 |issue=5331 |pages=1492–1495 |year=1997 |doi=10.1126/science.277.5331.1492 |bibcode=1997Sci...277.1492T |display-authors=etal}}</ref> + +The geological evolution of Ceres was dependent on the heat sources available during and after its formation: friction from [[planetesimal]] [[accretion (astrophysics)|accretion]], and decay of various [[radionuclide]]s (possibly including short-lived isotopes such as the [[cosmogenic nuclide]] [[aluminium-26]]). These are thought to have been sufficient to allow Ceres to differentiate into a rocky [[core (geology)|core]] and icy [[mantle (geology)|mantle]] soon after its formation.<ref name="Li2006" /><ref name="McCord2005" /> This process may have caused resurfacing by water [[volcanism]] and [[tectonics]], erasing older geological features.<ref name="McCord2005" /> Due to its small size, Ceres would have cooled early in its existence, causing all geological resurfacing processes to cease.<ref name="McCord2005" /><ref name="Castillo-Rogez2007">{{cite journal |last1=Castillo-Rogez |first1=J. C. |author2=McCord, T. B.; and Davis, A. G. |title=Ceres: evolution and present state |journal=Lunar and Planetary Science |volume=XXXVIII |pages=2006–2007 |year=2007 |url=http://www.lpi.usra.edu/meetings/lpsc2007/pdf/2006.pdf |format=PDF |accessdate=25 June 2009 }}</ref> Any ice on the surface would have gradually [[sublimation (chemistry)|sublimated]], leaving behind various hydrated minerals like clay minerals and [[Carbonate minerals|carbonates]].<ref name="Rivkin2006" /> + +Today, Ceres appears to be a geologically inactive body, with a surface sculpted only by [[impact crater|impacts]].<ref name="Li2006" /> The presence of significant amounts of water ice in its composition<ref name="Thomas2005" /> raises the possibility that Ceres has or had a layer of liquid water in its interior.<ref name="McCord2005" /><ref name="Castillo-Rogez2007" /> This hypothetical layer is often called an ocean.<ref name="Rivkin2006" /> If such a layer of liquid water exists, it is believed to be located between the rocky core and ice mantle like that of the theorized ocean on [[Europa (moon)|Europa]].<ref name="McCord2005" /> The existence of an ocean is more likely if [[solutes]] (i.e. [[salts]]), [[ammonia]], [[sulfuric acid]] or other [[antifreeze]] compounds are dissolved in the water.<ref name="McCord2005" /> + +==Potential habitability== +Although not as actively discussed as a [[Planetary habitability|potential home]] for [[microorganism|microbial]] [[extraterrestrial life]] as [[Life on Mars|Mars]], [[Life on Titan|Titan]], [[Life on Europa|Europa]] or [[Enceladus#Assessment of habitability|Enceladus]], the presence of water ice has led to speculation that life may exist there,<ref>{{cite web |url=http://www.universetoday.com/26587/life-on-ceres-could-the-dwarf-planet-be-the-root-of-panspermia/ |title=Life on Ceres: Could the Dwarf Planet be the Root of Panspermia |date=5 March 2009 |author=O'Neill, Ian |work=Universe Today |accessdate=30 January 2012 }}</ref><ref>{{cite book |author=Catling, David C. |year=2013 |title=Astrobiology: A Very Short Introduction |publisher=Oxford University Press |location=Oxford |isbn=0-19-958645-4 |page=99 }}</ref><ref>{{cite news | url=http://www.nbcnews.com/science/space/there-life-ceres-dwarf-planet-spews-water-vapor-n14506 | first=Alan | last=Boyle | title=Is There Life on Ceres? Dwarf Planet Spews Water Vapor | publisher=[[NBC]] | date=22 January 2014 | accessdate=10 February 2015}}</ref> and that hypothesized [[ejecta]] could have come from Ceres to Earth.<ref>[http://sciwww.esac.esa.int/SB/MARSEXPLORATION/docs/Presentations/Houtkooper.pdf "Glaciopanspermia: Seeding the Terrestrial Planets with Life?"] Joop M. Houtkooper, Institute for Psychobiology and Behavioral Medicine, Justus-Liebig-University, Giessen, Germany</ref> + +==Observation== +When Ceres has an opposition near the perihelion, it can reach a visual magnitude of +6.7.<ref name="Pasachoff1983">{{cite book |author=Menzel, Donald H.; and Pasachoff, Jay M. |year=1983 |title=A Field Guide to the Stars and Planets |edition=2nd |publisher=Houghton Mifflin |location=Boston, MA |isbn=978-0-395-34835-2 |page=391 }}</ref> This is generally regarded as too dim to be seen with the [[naked eye]], but under exceptional viewing conditions a very sharp-sighted person may be able to see it. Ceres was at its brightest (6.73) on 18 December 2012.<ref name="fact3">APmag and AngSize generated with [http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=1 Horizons] (Ephemeris: Observer Table: Quantities = 9,13,20,29) {{WebCite |url=http://www.webcitation.org/62D6JuAKM |date=5 October 2011 }}</ref> The only other asteroids that can reach a similarly bright magnitude are [[4 Vesta#Visibility|4 Vesta]], and, during rare oppositions near perihelion, [[2 Pallas#Characteristics|2 Pallas]] and [[7 Iris]].<ref>Martinez, Patrick, ''The Observer's Guide to Astronomy'', page 298. Published 1994 by Cambridge University Press</ref> At a [[astronomical conjunction|conjunction]] Ceres has a magnitude of around +9.3, which corresponds to the faintest objects visible with 10×50 [[binoculars]]. It can thus be seen with binoculars whenever it is above the horizon of a fully dark sky. + +Some notable observations and milestones for Ceres include: +*1984 November 13: An [[occultation]] of a [[star]] by Ceres observed in [[Mexico]], Florida and across the [[Caribbean]] .<ref name="Millis1987">{{cite journal |last1=Millis |first1=L. R. |author2=Wasserman, L. H.; Franz, O. Z. |title=The size, shape, density, and albedo of Ceres from its occultation of BD+8°471 |journal=Icarus |volume=72 |issue=3 |pages=507–518 |year=1987 |doi=10.1016/0019-1035(87)90048-0 |bibcode=1987Icar...72..507M |display-authors=etal}}</ref> +*1995 June 25: [[Ultraviolet]] [[Hubble Space Telescope]] images with 50&nbsp;km resolution.<ref name="Parker2002">{{cite journal |last1=Parker |first1=J. W. |author2=Stern, Alan S.; Thomas Peter C. |title=Analysis of the first disk-resolved images of Ceres from ultraviolet observations with the Hubble Space Telescope |year=2002 |journal=The Astrophysical Journal |volume=123 |issue=1 |pages=549–557 |bibcode=2002AJ....123..549P |doi=10.1086/338093 |arxiv=astro-ph/0110258 |display-authors=etal}}</ref><ref>{{cite web |url=http://www.swri.org/press/ceres.htm |title=Observations reveal curiosities on the surface of asteroid Ceres |accessdate=16 August 2006 |archiveurl=http://www.webcitation.org/62D6K1UXD |archivedate=5 October 2011 |deadurl=no }}</ref> +*2002: [[Infrared]] images with 30&nbsp;km resolution taken with the [[Keck telescope]] using [[adaptive optics]].<ref name="Keck">{{cite web |date=11 October 2006 |url=http://www.adaptiveoptics.org/News_1006_2.html |title=Keck Adaptive Optics Images the Dwarf Planet Ceres |publisher=Adaptive Optics |accessdate=27 April 2007 |archiveurl=http://www.webcitation.org/5msUtkSON |archivedate=18 January 2010 |deadurl=no }}</ref> +*2003 and 2004: Visible light images with 30&nbsp;km resolution (the best prior to the ''Dawn'' mission) taken using [[Hubble Space Telescope|Hubble]].<ref name="Li2006" /><ref name="Hubbl12003-4" /> +*2012 December 22: Ceres [[occultation|occulted]] the star TYC 1865-00446-1 over parts of Japan, Russia, and China.<ref name="asteroid">{{cite web |url=http://www.asteroidoccultation.com/2012_12/1222_1_27169.htm |title=Asteroid Occultation Updates |publisher=Asteroidoccultation.com |date=22 December 2012 |accessdate=20 August 2013|deadurl= yes| archivedate= 2012-07-12| archiveurl=http://web.archive.org/web/20120712103850/http://www.asteroidoccultation.com/2012_12/1222_1_27169.htm}}</ref> Ceres's brightness was magnitude 6.9 and the star, 12.2.<ref name="asteroid" /> +* 2014: Ceres was found to have an atmosphere with water vapor, confirmed by the [[Herschel Space Observatory|Herschel space telescope]].<ref>{{cite web |url=http://science.nasa.gov/science-news/science-at-nasa/2014/22jan_ceres |title=Water Detected on Dwarf Planet Ceres |publisher=Science.nasa.gov |date= |accessdate=24 January 2014 }}</ref> +* 2015: The NASA [[Dawn (spacecraft)|Dawn spacecraft]] approached and orbited Ceres, sending detailed images and scientific data back to Earth. + +==Exploration== +[[File:Dawn Flight Configuration 2.jpg|thumb|right|200px|Artist's conception of [[Dawn (spacecraft)|''Dawn'']], travelling from Vesta to Ceres]] +In 1981, a proposal for an asteroid mission was submitted to the [[European Space Agency]] (ESA). Named the Asteroidal Gravity Optical and Radar Analysis (AGORA), this [[spacecraft]] was to launch some time in 1990–1994 and perform two flybys of large asteroids. The preferred target for this mission was Vesta. AGORA would reach the asteroid belt either by a [[gravitational slingshot]] trajectory past Mars or by means of a small [[ion engine]]. However, the proposal was refused by ESA. A joint [[NASA]]–ESA asteroid mission was then drawn up for a Multiple Asteroid Orbiter with Solar Electric Propulsion (MAOSEP), with one of the mission profiles including an orbit of Vesta. NASA indicated they were not interested in an asteroid mission. Instead, ESA set up a technological study of a spacecraft with an ion drive. Other missions to the asteroid belt were proposed in the 1980s by France, Germany, Italy, and the United States, but none were approved.<ref name="ulivi_harland08">{{cite book + | author=Ulivi, Paolo; Harland, David | date=2008 + | title=Robotic Exploration of the Solar System: Hiatus and Renewal, 1983–1996 + | series=Springer Praxis Books in Space Exploration + | pages=117–125 | publisher=Springer | isbn=0-387-78904-9 }}</ref> Exploration of Ceres by fly-by and impacting penetrator was the second main target of the second plan of the multiaimed Soviet [[Vesta mission]], developed in cooperation with European countries for realisation in 1991–1994 but canceled due to the Soviet Union disbanding. +[[File:PIA17937-MarsCuriosityRover-FirstAsteroidImage-20140420.jpg|thumb|left|200px|First [[asteroid]] image (Ceres and Vesta) from [[Mars]] – viewed by [[Curiosity (rover)|''Curiosity'']] (20 April 2014)]] +In the early 1990s, NASA initiated the [[Discovery Program]], which was intended to be a series of low-cost scientific missions. In 1996, the program's study team recommended as a high priority a mission to explore the asteroid belt using a spacecraft with an [[ion thruster|ion engine]]. Funding for this program remained problematic for several years, but by 2004 the ''[[Dawn (spacecraft)|Dawn]]'' vehicle had passed its critical design review.<ref name="Russell2007">{{cite journal + | last=Russell + | first=C. T. + | author2=Capaccioni, F.; Coradini, A. + | title=Dawn Mission to Vesta and Ceres + | journal=Earth, Moon, and Planets + | volume=101 | issue=1–2 | pages=65–91 + |date=October 2007 + | doi=10.1007/s11038-007-9151-9 + | bibcode=2007EM&P..101...65R + | url= http://www-ssc.igpp.ucla.edu/personnel/russell/papers/dawn_mission_vesta_ceres.pdf + | accessdate=13 June 2011 |display-authors=etal}}</ref> + +It was launched on 27 September 2007, as the space mission to make the first visits to both Vesta and Ceres. On 3 May 2011, ''Dawn'' acquired its first targeting image 1.2 million kilometers from Vesta.<ref name="pr2011-138">{{cite web + |date=11 May 2011 + |title=NASA's Dawn Captures First Image of Nearing Asteroid + |publisher=NASA/JPL + |author=Cook, Jia-Rui C.; Brown, Dwayne C. + |url=http://www.jpl.nasa.gov/news/news.cfm?release=2011-138&amp;cid=release_2011-138 + |accessdate=14 May 2011}}</ref> After orbiting Vesta for 13 months, ''Dawn'' used its ion engine to depart for Ceres, with gravitational capture occurring on 6 March 2015<ref name="Schenk2015-01-15">{{cite web | last=Schenk | first=P. | title=Year of the 'Dwarves': Ceres and Pluto Get Their Due | publisher=[[Planetary Society]] | date=15 January 2015 | url= http://www.planetary.org/blogs/guest-blogs/2015/0115-year-of-the-dwarves-ceres-and-pluto.html | accessdate=10 February 2015 }}</ref> at a separation of 61,000&nbsp;km,<ref name = "Rayman2014.12.01">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/marc-rayman/20141201-dawn-journal-looking-ahead-at-ceres.html |title=Dawn Journal: Looking Ahead at Ceres |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=1 December 2014 |accessdate=2 March 2015}}</ref> four months prior to the ''[[New Horizons]]'' flyby of [[Pluto]]. + +''Dawn's'' mission profile calls for it to study Ceres from a series of circular polar orbits at successively lower altitudes. It entered its first observational orbit ("RC3") around Ceres at an altitude of 13,500&nbsp;km on 23 April 2015, staying for only approximately one orbit (fifteen days).<ref name = "Rayman2015.03.06" /><ref name = "Rayman2014.03.03">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/marc-rayman/20140303-dawn-journal-maneuvering-around-ceres.html |title=Dawn Journal: Maneuvering Around Ceres |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=3 March 2014 |accessdate=6 March 2015}}</ref> The spacecraft will subsequently reduce its orbital distance to 4,400&nbsp;km for its second observational orbit ("survey") for three weeks,<ref name = "Rayman2014.05.07">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/marc-rayman/20140430-dawn-journal-explaining-orbit-insertion.html |title=Dawn Journal: Explaining Orbit Insertion |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=30 April 2014 |accessdate=6 March 2015}}</ref> then down to 1,470&nbsp;km ("HAMO") for two months<ref name = "Rayman2014.07.01">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/marc-rayman/20140701-dawn-journal-hamo-at-ceres.html |title=Dawn Journal: HAMO at Ceres |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=30 June 2014 |accessdate=6 March 2015}}</ref> and then down to its final orbit at 375&nbsp;km ("LAMO") for at least three months.<ref name = "Rayman2014.09.02">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/marc-rayman/20140902-dawn-journal-from-hamo-to-lamo.html |title=Dawn Journal: From HAMO to LAMO and Beyond |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=31 August 2014 |accessdate=6 March 2015}}</ref> The spacecraft instrumentation includes a framing camera, a visual and infrared [[spectrometer]], and a [[gamma-ray]] and [[neutron]] detector. These instruments will examine Ceres's shape and elemental composition.<ref name="Russel2006">{{cite journal |last1=Russel |first1=C. T. |author2=Capaccioni, F.; Coradini, A. |title=Dawn Discovery mission to Vesta and Ceres: Present status |journal=Advances in Space Research |volume=38 |issue=9 |pages=2043–2048 |year=2006 |doi=10.1016/j.asr.2004.12.041 |bibcode=2006AdSpR..38.2043R |display-authors=etal}}</ref> On 13 January 2015, ''Dawn'' took the first images of Ceres at near-Hubble resolution, revealing impact craters and a small high-albedo spot on the surface, near the same location as that observed previously. Additional photo sessions, at increasingly better resolution took place on 25 January, 4, 12, 19, and 25 February, 1 March, and 10 and 15 April.<ref name = "Rayman2015.01.30">{{cite web |url= http://www.planetary.org/blogs/guest-blogs/marc-rayman/20150130-dawn-journal-closing-in-on-ceres.html|title= Dawn Journal: Closing in on Ceres |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=30 January 2015 |accessdate=2 March 2015}}</ref> + +''Dawn''{{'s}} arrival in a stable orbit around Ceres was delayed after, close to reaching Ceres, it was hit by a [[cosmic ray]], making it take another, longer route around Ceres in back, instead of a direct spiral towards it. + +The [[China National Space Administration|Chinese Space Agency]] is designing a sample retrieval mission from Ceres that would take place during the 2020s.<ref>[http://english.nssc.cas.cn/ns/NU/201410/W020141016603613379886.pdf China's Deep-space Exploration to 2030 by Zou Yongliao Li Wei Ouyang Ziyuan Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, Beijing]</ref> +{{clear}} + +==Maps== +{| class="wikitable" style="margin:0.5em auto; width:700px;" +| <center>[[File:PIA19063-Ceres-DwarfPlanet-DawnMission-March2015.jpg|700px]]</center> +<center>Exaggerated-color photographic map of Ceres, centered on 180° longitude (March 2015)</center> +|- +| <center>[[File:USGS-Ceres-Nomenclature-20150713.jpg|800px]]</center> +<center>Black-and-white photographic map of Ceres, centered on 0° longitude, with official nomenclature ([[USGS]]) (July 2015)</center> +|- +| <center>[[File:PIA19606-Ceres-Dawn-GlobalMap-Annotated-20150728.jpg|700px]]</center> +<center>Topographic map of Ceres (July 2015). 15&nbsp;km (10&nbsp;mi) of elevation separate the lowest crater floors (indigo) from the highest peaks (white).<ref name="NASA-20150728-el">{{cite web |last=Landau |first=Elizabeth |title=New Names and Insights at Ceres |url=http://www.jpl.nasa.gov/news/news.php?feature=4669 |date=28 July 2015 |work=[[NASA]] |accessdate=28 July 2015 }}</ref></center> +|- +| <center>[[File:PIA19607-Ceres-Dawn-TopographicMaps-EastWestHemispheres-20150728.jpg|700px]]</center> +<center>Hemispheric topographic maps of Ceres, centered on 60° and 240° east longitude (July 2015).</center> +|} + +===Map of quadrangles=== +The following [[imagemap]] of the dwarf planet Ceres is divided into 15 quadrangles &ndash; which may be provisional at the present time.<ref name="TPS-20150319">{{cite web |last=Lakdawalla |first=Emily |title=The Planetary Society Blogs - LPSC 2015: First results from Dawn at Ceres: provisional place names and possible plumes |url=http://www.planetary.org/blogs/emily-lakdawalla/2015/03191629-lpsc-2015-dawn-at-ceres.html |date=19 March 2015 |work=[[The Planetary Society]] |accessdate=21 June 2015 }}</ref> North is at the top; 0 East is at the far left on the equator. The map image(s) were taken by the [[Dawn (spacecraft)|''Dawn'']] space probe. +{{clear}} +{{Ceres Quads - By Name}} + +==Gallery== +{| class="wikitable" style="margin:0.5em auto; width:600px;" +|- +| style="font-size:88%" | [[File:PIA19310-Ceres-DwarfPlanet-20150225.jpg|600px]] +<center>Ceres in half shadow from 40,000&nbsp;km (25 February 2015)</center> +|} +{| class="wikitable" style="margin:0.5em auto; width:700px;" +|- +| style="font-size:88%" | [[File:PIA18923-Ceres-DwarfPlanet-CrateredSurface-20150219.jpg|700px]] +<center>''Dawn'' Ceres mosaic – 19 February 2015</center> +|} +{{Double image|center|PIA19183 Ceres approach 2015-02-19.jpg|347|PIA19056-Ceres-DawnSpacecraft-20150212.jpg|346|Ceres from ''Dawn'', {{convert|29,000|mi|disp=flip|sp=us}} away. At this distance, Ceres is approximately the apparent size of the full moon (19 February 2015). The large [[impact basin]] in the lower portion of the left image appears relatively young.<ref name = "Krummheuer2015.02.25">{{cite web | last = Krummheuer | first = B. | date = 25 February 2015 | accessdate = 26 February 2015 + | title = Dawn: Two new glimpses of dwarf planet Ceres + | publisher = [[Max Planck Institute for Solar System Research]] + | url = http://www.mps.mpg.de/3937030/PM_2015_02_25_Dawn_Zwei_neue_Ansichten_des_Zwergplaneten_Ceres + | archiveurl = | archivedate = }}</ref>|Ceres at {{convert|52,000|mi|disp=flip|sp=us}} away (12 February 2015), at half the apparent size of the full moon. Relative to these images, those at left were taken at similar longitudes but a more northerly latitude,<ref name = "Rayman2015.02.25">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/marc-rayman/0225-dawn-journal-ceres-deepening-mysteries.html |title=Dawn Journal: Ceres' Deepening Mysteries |publisher=[[Planetary Society]] |first=Marc |last=Rayman |date=25 February 2015 |accessdate=25 February 2015}}</ref> and are rotated approximately 45° clockwise.}} +<gallery class="center"> +File:Ceres optimized.jpg|2004<br>[[Hubble Space Telescope]] +File:PIA19064-Ceres-DwarfPlanet-StillImage-20150414.jpg|14 April 2015; ''Dawn''<br>{{convert|22000|km|mi|abbr=on}} +File:PIA19547-Ceres-DwarfPlanet-Dawn-RC3-AnimationFrame25-20150504.jpg|4 May 2015; ''Dawn''<br>{{convert|13600|km|mi|abbr=on}}<br>{{small|([[:File:PIA19319-Ceres-DwarfPlanet-Dawn-RC3-image1-20150426.jpg|1]];[[:File:PIA19321-Ceres-DwarfPlanet-Dawn-RC3-image2-20150426.jpg|2]];[[:File:PIA19322-Ceres-DwarfPlanet-Dawn-RC3-image3-20150426.jpg|3]];[[:File:PIA19323-Ceres-DwarfPlanet-Dawn-RC3-image4-20150426.jpg|4]];[[:File:PIA19536-Ceres-DwarfPlanet-Dawn-RC3-image5-20150426.jpg|5]];[[:File:PIA19538-Ceres-DwarfPlanet-Dawn-RC3-image6-20150426.jpg|6]];[[:File:PIA19540-Ceres-DwarfPlanet-Dawn-RC3-image7-20150426.jpg|7]];[[:File:PIA19542-Ceres-DwarfPlanet-Dawn-RC3-image8-20150504.jpg|8]];[[:File:PIA19543-Ceres-DwarfPlanet-Dawn-RC3-image9-20150504.jpg|9]];[[:File:PIA19544-Ceres-DwarfPlanet-Dawn-RC3-image10-20150504.jpg|10]];[[:File:PIA19545-Ceres-DwarfPlanet-Dawn-RC3-image11-20150504.jpg|11]];[[:File:PIA19546-Ceres-DwarfPlanet-Dawn-RC3-image12-20150504.jpg|12]];[[:File:PIA19548-Ceres-DwarfPlanet-Dawn-RC3-image13-20150429.jpg|13]];[[:File:PIA19549-Ceres-DwarfPlanet-Dawn-RC3-image14-20150429.jpg|14]];[[:File:PIA19550-Ceres-DwarfPlanet-Dawn-RC3-image15-20150429.jpg|15]];[[:File:PIA19551-Ceres-DwarfPlanet-Dawn-RC3-image16-20150501.jpg|16]];[[:File:PIA19552-Ceres-DwarfPlanet-Dawn-RC3-image17-20150429.jpg|17]];[[:File:PIA19553-Ceres-DwarfPlanet-Dawn-RC3-image18-20150504.jpg|18]];[[:File:PIA19562-Ceres-DwarfPlanet-Dawn-RC3-image19-20150506.jpg|19]];[[:File:PIA19554-Ceres-DwarfPlanet-Dawn-RC3-image20-20150507.jpg|20]];[[:File:PIA19555-Ceres-DwarfPlanet-Dawn-RC3-image21-20150507.jpg|21]];[[:File:PIA19556-Ceres-DwarfPlanet-Dawn-RC3-image22-20150507.jpg|22]];[[:File:PIA19557-Ceres-DwarfPlanet-Dawn-RC3-image23-20150507.jpg|23]];[[:File:PIA19558-Ceres-DwarfPlanet-Dawn-RC3-image24-20150507.jpg|24]]) (3D: [[:File:PIA19320-Ceres-DwarfPlanet-Anaglyph-20150426.jpg|1]];[[:File:PIA19537-Ceres-DwarfPlanet-Dawn-RC3-Anaglyph5-20150426.jpg|5]];[[:File:PIA19539-Ceres-DwarfPlanet-Dawn-RC3-Anaglyph6-20150426.jpg|6]];[[:File:PIA19541-Ceres-DwarfPlanet-Dawn-RC3-Anaglyph7-20150426.jpg|7]]) ([[:File:PIA19547-Ceres-DwarfPlanet-Dawn-RC3-Animation-20150504.gif|animation]])}} +File:PIA19559-Ceres-DwarfPlanet-Dawn-OpNav8-image1-20150516.jpg|16 May 2015; ''Dawn''<br>{{convert|7500|km|mi|abbr=on}}<br>{{small|([[:File:PIA19559-Ceres-DwarfPlanet-Dawn-OpNav8-image1-20150516.jpg|1]];[[:File:PIA19560-Ceres-DwarfPlanet-Dawn-OpNav8-image2-20150516.jpg|2]];[[:File:PIA19561-Ceres-DwarfPlanet-Dawn-OpNav8-image3-20150516.jpg|3]])}} +</gallery> +<gallery class="center">File:PIA19563-Ceres-DwarfPlanet-Dawn-OpNav9-image1-20150522.jpg|22 May 2015; ''Dawn''<br>{{convert|5100|km|mi|abbr=on}}<br>{{small|([[:File:PIA19563-Ceres-DwarfPlanet-Dawn-OpNav9-image1-20150522.jpg|1]];[[:File:PIA19564-Ceres-DwarfPlanet-Dawn-OpNav9-image2-20150522.jpg|2]];[[:File:PIA19565-Ceres-DwarfPlanet-Dawn-OpNav9-image3-20150522.jpg|3]];[[:File:PIA19566-Ceres-DwarfPlanet-Dawn-OpNav9-image4-20150522.jpg|4]];[[:File:PIA19567-Ceres-DwarfPlanet-Dawn-OpNav9-image5-20150522.jpg|5]])}} +File:Ezinu and Nawish craters in context.jpg|23 May 2015; ''Dawn''<br>{{convert|5100|km|mi|abbr=on}}<br>Context view +File:PIA19065-Ceres-DwarfPlanet-Dawn-OpNav9-image1-20150523.jpg|23 May 2015; ''Dawn''<br>{{convert|5100|km|mi|abbr=on}}<br> Close-up view +File:PIA19579-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image11-20150609.jpg|6 June 2015: ''Dawn''<br>{{convert|4400|km|mi|abbr=on}}<br>{{small|([[:File:Occator crater.jpg|1]];[[:File:PIA19569-Ceres-DwarfPlanet-Dawn-SouthernHemisphere-2ndMappingOrbit-20150606.jpg|2]];[[:File:PIA19570-Ceres-DwarfPlanet-Dawn-NorthernHemisphere-2ndMappingOrbit-20150606.jpg|3]];[[:File:PIA19572-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image4-20150606.jpg|4]];[[:File:PIA19573-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image5-20150606.jpg|5]];[[:File:PIA19574-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image6-20150606.jpg|6]];[[:File:PIA19575-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image7-20150609.jpg|7]];[[:File:PIA19576-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image8-20150606.jpg|8]];[[:File:PIA19577-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image9-20150605.jpg|9]];[[:File:PIA19578-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image10-20150614.jpg|10]];[[:File:PIA19579-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image11-20150609.jpg|11]];[[:File:PIA19580-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image12-20150607.jpg|12]];[[:File:PIA19581-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image13-20150609.jpg|13]];[[:File:PIA19582-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image14-20150609.jpg|14]];[[:File:PIA19583-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image15-20150610.jpg|15]];[[:File:PIA19584-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image16-20150615.jpg|16]];[[:File:PIA19585-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image17-20150616.jpg|17]];[[:File:PIA19586-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image18-20150618.jpg|18]];[[:File:PIA19587-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image19-20150618.jpg|19]];[[:File:PIA19588-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image20-20150622.jpg|20]];[[:File:PIA19589-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image21-20150617.jpg|21]];[[:File:PIA19590-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image22-20150618.jpg|22]];[[:File:PIA19591-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image23-20150622.jpg|23]];[[:File:PIA19592-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image24-20150621.jpg|24]];[[:File:PIA19593-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image25-20150624.jpg|25]];[[:File:PIA19594-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image26-20150624.jpg|26]];[[:File:PIA19595-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image27-20150624.jpg|27]];[[:File:PIA19596-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image28-20150625.jpg|28]];[[:File:PIA19597-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image29-20150625.jpg|29]];[[:File:PIA19599-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image30-20150624.jpg|30]];[[:File:PIA19600-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image31-20150625.jpg|31]];[[:File:PIA19601-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image32-20150625.jpg|32]];[[:File:PIA19602-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image33-20150625.jpg|33]];[[:File:PIA19603-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image34-20150625.jpg|34]];[[:File:Dawn Survey Orbit Image 35.jpg|35]];[[:File:PIA19609-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image36-20150624.jpg|36]];[[:File:PIA19610-Ceres-DwarfPlanet-Dawn-2ndMappingOrbit-image37-20150624.jpg|37]])}} +</gallery> + +===Animations=== +<gallery class=center> +File:PIA19179-Ceres-DawnSpacecraft-Animation16-20150204.gif|4 February 2015; ''Dawn''<br>{{convert|90,000|km|mi|abbr=on}} +File:PIA18920-Ceres-DwarfPlanet-Animation-20150219.gif|19 February 2015; ''Dawn''<br>{{convert|29,000|km|mi|abbr=on}} +File:PIA19547-Ceres-DwarfPlanet-Dawn-RC3-Animation-20150504.gif|4 May 2015; ''Dawn''<br>{{convert|13,600|km|mi|abbr=on}} +File:Ceres spots animation May 4 2015.gif|4 May 2015; ''Dawn''<br>{{convert|13,600|km|mi|abbr=on}}<br>[[Bright spots on Ceres|bright spots]] +</gallery> +[[File:Video-FlyOver-DwarfPlanet-Ceres--Dawn-20150608.ogv|thumb|center|300px|<center>[[:File:Video-FlyOver-DwarfPlanet-Ceres--Dawn-20150608.ogv|Video]] - Fly Over dwarf planet Ceres at {{convert|13600|km|mi|abbr=on}} away (8 June 2015).<ref name="NASA-20150608-a">{{cite web |last1=Landau |first1=Elizabeth |last2=Dyches |first2=Preston |title=Fly Over Ceres in New Video |url=http://www.jpl.nasa.gov/news/news.php?feature=4614 |date=8 June 2015 |work=[[NASA]] |accessdate=9 June 2015 }}</ref></center>]] + +==See also== +{{Portal|Solar System}} +{{Wikipedia books|1=Solar System}} * [[Ceres in fiction]] * [[Colonization of Ceres]] -* [[Keres (mythology)]], death spirits unconnected with Ceres -* [[Series (disambiguation)]] -* [[Seris]] +* [[Planet#Objects formerly considered planets|Former classification of planets]] +* [[List of notable asteroids]] +* [[List of Solar System objects by size]] + +==Notes== +{{reflist|group=lower-alpha}} + +==References== +{{Reflist|30em}} + +==External links== +{{Commons category|Ceres (dwarf planet)}} +* [http://dawn.jpl.nasa.gov/ Dawn mission home page] at JPL +* [http://orbitsimulator.com/gravity/articles/ceres.html A simulation of the orbit of Ceres] +* [http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=1 JPL Ephemeris] +* [http://www.keplersdiscovery.com/Asteroid.html How Gauss determined the orbit of Ceres] from keplersdiscovery.com +* {{cite journal |last=Hilton |first=James L. |title=U.S. Naval Observatory Ephemerides of the Largest Asteroids |url=http://aa.usno.navy.mil/publications/reports/asteroid_ephemerides.html |journal=The Astronomical Journal |volume=117 |page=1077 |year=1999 |bibcode=1999AJ....117.1077H |doi=10.1086/300728 |issue=2 }}<!--not an accurate mass determination, but interesting reading, and online--> +* [http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=35232 Map of Ceres] based on ''Dawn'''s 19 February 2015 images (NASA/JPL/UCLA/MPS/DLR/IDA/"Gerald"/Phil Stooke) – from [http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218563 forum post] by Phil Stooke +* [http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=35235 Northern] and [http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=35231 southern] hemisphere maps – polar azimuthal projections (NASA/JPL/UCLA/MPS/DLR/IDA/"Gerald"/Phil Stooke) – from [http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218574 forum] [http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218559 posts] by Phil Stooke +* [http://imgur.com/4B1TfHg Animated reprojected colorized map of Ceres] (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/HST/Phil Stooke/"Gerald") uploaded 22 February 2015 (larger version [http://gifuk.com/s/7fc5e2c1593977d4 here]) +* [http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=35237 Colorized map of Ceres](NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/HST/"Gerald"/Phil Stooke/"Herobrine") from [http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218581 forum post] by "Herobrine" +* [http://imgur.com/NMw6CE2 Animated Ceres map] (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/"Gerald") showing changes as a function of solar time, from [http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218650 forum post] by "Gerald" +* [http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=35212 Pairs of Ceres images] for cross-eyed stereo, from [http://www.unmannedspaceflight.com/index.php?s=&showtopic=7960&view=findpost&p=218615 forum post] by "algorimancer" + +{{Ceres}} +{{Dwarf planets}} +{{Solar System}} +{{Minor planets navigator|PageName=1 Ceres||2 Pallas|state=autocollapse}} +{{Small Solar System bodies}} +{{Featured article}} + +{{Authority control}} -{{disambiguation|geo}} +{{DEFAULTSORT:000001)}} +[[Category:Minor planets named from Roman mythology|Ceres]] +[[Category:Minor planets visited by spacecraft|20150306]] +[[Category:Astronomical objects discovered in 1801|18010101]] +[[Category:Ceres (dwarf planet)| ]] +[[Category:C-type asteroids (SMASS)]] +[[Category:G-type asteroids (Tholen)]] +[[Category:Numbered asteroids]] +[[Category:Discoveries by Giuseppe Piazzi]] +[[Category:Objects formerly considered planets]] +[[Category:Solar System objects in hydrostatic equilibrium]] '