View source for Kepler-10

{{Short description|Sunlike star in the constellation Draco}}
{{good article}}
{{Starbox begin
| name = Kepler-10
}}
{{Starbox image
| image = [[File:Kepler-10 star system.jpg|250px]]
| caption = An artist's depiction of the Kepler-10 system. [[Kepler-10c]] is in the foreground.
}}
{{Starbox observe
| constell = [[Draco (constellation)|Draco]]
| epoch = J2000
| ra = {{RA|19|02|43.06139}}<ref name="GaiaDR3"/>
| dec = {{DEC|+50|14|28.7016}}<ref name="GaiaDR3"/>
| appmag_v = 11.157<ref name="harps"/>
}}
{{Starbox character
| class = G2V<ref name="SIMBAD"/>
}}
{{Starbox astrometry
| radial_v = {{val|-98.44|0.24}}<ref name="GaiaDR3"/>
| prop_mo_ra = {{val|−18.483}}
| prop_mo_dec = {{val|41.382}}
| pm_footnote = <ref name="GaiaDR3"/>
| parallax = 5.3698
| p_error = 0.0103
| parallax_footnote = <ref name="GaiaDR3"/>
}}
{{Starbox detail
| mass = {{val|0.910|0.021}}<ref name="harps"/>
| radius = {{val|1.065|0.009}}<ref name="harps"/>
| temperature = {{val|5708|28}}<ref name="harps"/>
| metal_fe = {{val|-0.15|0.04}}<ref name="Bonomo2023"/>
| age_gyr = 3.7–{{val|10.6|1.5|1.3}}<ref name="harps"/>
}}
{{Starbox catalog
| names = {{odlist | 2MASS=J19024305+5014286 | KOI=72 | KIC=11904151 | GSC=03549-00354 }}<ref name="SIMBAD"/>
}}
{{Starbox reference
| Simbad = Kepler-10
| KIC = 11904151
}}
{{Starbox end}}
'''Kepler-10''', formerly known as '''KOI-72''', is a [[Sun-like star]] in the constellation of [[Draco (constellation)|Draco]] that lies {{convert|607|ly|pc|lk=on|abbr=off}} from Earth.<ref name="epe" /><ref>{{Cite web|url=https://exoplanets.nasa.gov/resources/17/kepler-10-stellar-family-portrait/|title=Kepler-10 Stellar Family Portrait|website=[[NASA]]|access-date=22 February 2023}}</ref> Kepler-10 was targeted by [[NASA]]'s [[Kepler space telescope]], as it was seen as the first star identified by the Kepler mission that could be a possible host to a small, transiting exoplanet.<ref name=announcement /> The star is slightly less massive, slightly larger, and slightly cooler than the Sun; at an estimated 11.9 billion years in age, Kepler-10 is 2.3 times the age of the Sun.<ref name="harps" /> 

Kepler-10 is host to a [[planetary system]] made up of at least three planets. [[Kepler-10b]], the first undeniably rocky planet,<ref name=announcement /> was discovered in its orbit after eight months of observation and announced on January 10, 2011. The planet orbits its star closely, completing an orbit every 0.8 days,<ref name=NASA /> and has a density similar to that of iron.<ref name=announcement /> The second planet, [[Kepler-10c]], was confirmed on May 23, 2011, based on follow-up observations by the [[Spitzer Space Telescope]]. The data shows it has an orbital period of 42.3 days and has a radius more than double that of Earth, but it was initially thought to have a higher density, making it the largest and most massive rocky planet discovered as of June 2014.<ref name="harps"/><ref name=Fressin2011 /><ref name="NASA-20140602">{{cite web |last=Clavin |first=Whitney |title=Astronomers Confounded By Massive Rocky World |url=http://www.jpl.nasa.gov/news/news.php?release=2014-171 |date=June 2, 2014 |work=[[NASA]] |access-date=June 3, 2014 }}</ref> However, refined mass measurements have shown it to be a more typical volatile-rich planet.<ref name=Rajpaul/> A third planet, Kepler-10d, was discovered in 2023 by [[Doppler spectroscopy|radial velocity]] observations.<ref name="Bonomo2023"/>

==Nomenclature and history==
Kepler-10 was named because it was the tenth planetary system observed by the Kepler spacecraft, a NASA satellite designed to search for [[terrestrial planet|Earth-like planets]] that [[transit method|transit]], or cross in front of, their host stars with respect to [[Earth]]. The transit slightly dims the host star; this periodic dimming effect is then noted by Kepler.<ref name="Mission overview"/> After eight months of observation ranging from May 2009 to January 2010, the Kepler team established Kepler-10b as the first rocky exoplanet discovered by the Kepler satellite. Kepler-10 was the first  Kepler-targeted star suspected of having a small planet in orbit. Because of that, verifying Kepler's discovery was prioritized by telescopes at the [[W.M. Keck Observatory]] in Hawaii. The discovery was successfully verified.<ref name=announcement>{{cite web |url=http://www.kepler.nasa.gov/news/nasakeplernews/index.cfm?FuseAction=ShowNews&NewsID=94 |archive-url=https://web.archive.org/web/20110110184623/http://kepler.nasa.gov/news/nasakeplernews/index.cfm?FuseAction=ShowNews&NewsID=94 |url-status=dead |archive-date=10 January 2011 |title=NASA'S Kepler Mission Discovers Its First Rocky Planet |author1=Perrotto, Trent J. |author2=Hoover, Rachel |date=10 January 2011 |work=[[Ames Research Center]] |publisher=[[NASA]] |access-date=13 March 2011}}</ref> Although there had been many ''potentially'' rocky exoplanets discovered in the past, Kepler-10b was the first ''definitively'' rocky planet to have been discovered.<ref name=NG>{{cite web |url=http://news.nationalgeographic.com/news/2011/01/110110-nasa-kepler-10b-new-planet-found-rocky-science-space/ |archive-url=https://web.archive.org/web/20110112152638/http://news.nationalgeographic.com/news/2011/01/110110-nasa-kepler-10b-new-planet-found-rocky-science-space/ |url-status=dead |archive-date=January 12, 2011 |title=NASA Finds Smallest Earthlike Planet Outside Solar System |author=Richard A. Lovett |date=10 January 2011 |publisher=[[National Geographic Society]] |access-date=13 March 2011}}</ref>

The discovery of Kepler-10b was announced to the public at a winter meeting of the [[American Astronomical Society]] on January 10, 2011 in Seattle.<ref name=NG />  On May 23, 2011, the existence of Kepler-10c was confirmed at the 218th AAS meeting in Boston.<ref name="sciam"/>

==Characteristics==
Kepler-10 is a [[G-type star|G-type]] star, like the [[Sun]]. With a mass of 0.895 (± 0.06) [[solar mass|M<sub>sun</sub>]] and a radius of 1.056 (± 0.021) [[solar radius|R<sub>sun</sub>]], the star is approximately 10% less massive than and 5% wider than the Sun. The [[metallicity]] of Kepler-10, as measured in [Fe/H] (the amount of [[iron]] in the star), is -0.15 (± 0.04); this means that Kepler-10 is about 70% as metal-rich as the Sun. Metallicity tends to play a large role in the formation of planets, determining if they form, and what kind of planet they will form.<ref>{{cite web |url=http://www.spacedaily.com/news/extrasolar-04zl.html |title=Extrasolar Planets: A Matter of Metallicity |author=Henry Bortman |date=12 October 2004 |publisher=Space Daily |access-date=13 March 2011}}</ref> In addition, Kepler-10 is estimated to be 11.9 billion years old and to have an [[effective temperature]] of 5627 (± 44) [[Kelvin scale|K]];<ref name=epe>{{cite encyclopedia|url=http://www.exoplanet.eu/star.php?st=Kepler-10 |title=Notes for star Kepler-10 |date=2011 |access-date=13 March 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110121143507/http://exoplanet.eu/star.php?st=Kepler-10 |encyclopedia=[[Extrasolar Planets Encyclopaedia]] |archive-date=21 January 2011 }}</ref> To compare, the Sun is younger and hotter, with an age of 4.6 billion years<ref>{{cite web |url=http://www.universetoday.com/18237/how-old-is-the-sun/ |title=How Old is the Sun? |author=Fraser Cain |date=16 September 2008 |publisher=Universe Today |access-date=13 March 2011}}</ref> and an effective temperature of 5778 K.<ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html |title=Sun Fact Sheet |author=Ed Grayzeck |work=[[Goddard Space Flight Center]] |publisher=[[NASA]] |access-date=13 March 2011}}</ref>

Kepler-10 is located at a distance of 186 parsecs from the Earth, which equates to approximately 607 light years. Also, Kepler-10's [[apparent magnitude]], or brightness as seen from Earth, is 10.96; it therefore cannot be seen with the [[naked eye]].<ref name=epe /> [[File:Kepler10b artist.jpg|thumb|right|200px|An artist's impression of planet [[Kepler-10b]].]]

==Planetary system==
Per the usual [[Extrasolar planet#Nomenclature|exoplanet nomenclature]], the first planet discovered to be orbiting Kepler-10 is called [[Kepler-10b]].  Announced in 2011, it was the first definitely [[rocky planet]] identified outside the Solar system.  The planet has a mass that is 3.33±0.49 times that of Earth's and a radius that is 1.47{{±|0.03|0.02}} times that of Earth.<ref name="harps"/> The planet orbits Kepler-10 at a distance of 0.01684 [[astronomical unit|AU]] every 0.8375 days; this can be compared to the orbit and [[orbital period]] of planet [[Mercury (planet)|Mercury]], which circles the Sun at a distance of 0.3871 AU every 87.97 days.<ref>{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact.html |title=Mercury Fact Sheet |author=David Williams |date=17 November 2010 |work=[[Goddard Space Flight Center]] |publisher=[[NASA]] |access-date=27 February 2011}}</ref> Because the planet orbits so closely to its star, its [[Orbital eccentricity|eccentricity]] is virtually zero. It, thus, has an extremely circular orbit.<ref name=NASA />

[[Kepler-10c]]<ref name="Fressin2011"/> was also discovered by NASA's [[Kepler Mission]],<ref name="NASANews"/> the second exoplanet found to orbit Kepler-10. Radial-velocity measurements of the body initially suggested that it has a mass of 17.2±1.9 Earth masses and a radius of 2.35 Earth radii, which would have made it the largest known rocky planet {{as of|2014|lc=y}}. Kepler-10c would orbit Kepler-10 at a distance of 0.24 AU every 45.29 days.<ref name="harps"/> However, in July 2017, more careful analysis of HARPS-N and HIRES data showed that Kepler-10c was much less massive than originally thought, instead around {{val|7.37|1.32|1.19}} {{Earth mass}} with a mean density of 3.14 g/cm<sup>3</sup>. Instead of a primarily rocky composition, the more accurately determined mass of Kepler-10c suggests a world made almost entirely of volatiles, mainly water.<ref name=Rajpaul/>

A candidate third planet with an orbital period of about 102 days, given the provisional designation KOI-72.X, was identified in 2016 based on [[transit-timing variation]]s.<ref name="Weiss2016"/><ref name=Rajpaul/> In 2023, the presence of a third planet, Kepler-10d, was confirmed by [[Doppler spectroscopy|radial velocity]] observations. It has an orbital period of 151 days and a [[minimum mass]] about 13 times that of Earth.<ref name="Bonomo2023"/>

{{OrbitboxPlanet begin
| table_ref = <ref name="Bonomo2023"/>
}}
{{OrbitboxPlanet
| exoplanet = [[Kepler-10b|b]]
| mass_earth = {{val|3.26|0.30}}
| radius_earth = {{val|1.470|0.030|0.020}}
| period = {{val|0.8374907|0.0000002}}
| semimajor = {{val|0.01685|0.00013}}
| inclination = {{val|84.8|3.2|3.9}}
| eccentricity = 0
}}
{{OrbitboxPlanet
| exoplanet = [[Kepler-10c|c]]
| mass_earth = {{val|11.4|1.3}}
| radius_earth = {{val|2.355|0.022}}
| period = {{val|45.294301|0.000048}}
| semimajor = {{val|0.2410|0.0019}}
| inclination = {{val|89.623|0.011}}
| eccentricity = {{val|0.130|0.050}}
}}
{{OrbitboxPlanet
| exoplanet = d
| mass_earth = {{val|12.68|2.24|p=≥}}
| radius_earth = 
| period = {{val|151.04|0.45}}
| semimajor = {{val|0.5379|0.0044}}
| inclination = 
| eccentricity = <0.26
}}
{{Orbitbox end}}

==See also==
* [[Kepler Mission]]
* [[List of exoplanets]]

==References==
{{reflist|refs=

<ref name="GaiaDR3">{{Cite Gaia DR3|2132155017099178624}}</ref>

<ref name="Fressin2011">{{cite journal | title=Kepler-10c, A 2.2-Earth Radius Transiting Planet In A Multiple System | last1=Fressin | first1=François | last2=Torres | first2=Guillermo | last3=Désert | first3=Jean-Michel | last4=Charbonneau | first4=David | last5=Batalha | first5=Natalie M. | last6=Fortney | first6=Jonathan J. | last7=Rowe | first7=Jason F. | last8=Allen | first8=Christopher|last9=Borucki|first9=William J.|last10=Brown|first10=Timothy M.|last11=Bryson|first11=Stephen T.|last12=Ciardi|first12=David R.|last13=Cochran|first13=William D.|last14=Deming|first14=Drake|last15=Dunham|first15=Edward W. | last16=Fabrycky | first16=Daniel C. | last17=Gautier III | first17=Thomas N. | last18=Gilliland | first18=Ronald L. | last19=Henze | first19=Christopher E. | last20=Holman | first20=Matthew J. | last21=Howell | first21=Steve B. | last22=Jenkins | first22=Jon M. | last23=Kinemuchi | first23=Karen | last24=Knutson | first24=Heather | last25=Koch | first25=David G. | last26=Latham | first26=David W. | last27=Lissauer | first27=Jack J. | last28=Marcy | first28=Geoffrey W. | last29=Ragozzine | first29=Darin | last30=Sasselov | first30=Dimitar D. | last31=Still | first31=Martin | last32=Tenenbaum | first32=Peter | last33=Uddin | first33=Kamal | display-authors=1 | journal=The Astrophysical Journal Supplement Series | volume=197 | issue=1 | at=5 | year=2011 | arxiv=1105.4647 | bibcode=2011ApJS..197....5F | bibcode-access=free | doi=10.1088/0067-0049/197/1/5 | doi-access=free }}</ref>

<ref name="Mission overview">{{cite web | title=Mission overview | url=https://www.nasa.gov/mission_pages/kepler/overview/index.html | work=Kepler and K2 | date=13 April 2015 | publisher=NASA | access-date=9 August 2020}}</ref>

<ref name="NASA">{{cite web |url=http://kepler.nasa.gov/Mission/discoveries/  |archive-url=https://web.archive.org/web/20100527104316/http://kepler.nasa.gov/Mission/discoveries/  |url-status=dead  |archive-date=2010-05-27  |title=Summary Table of Kepler Discoveries |date=2011 |publisher=NASA|access-date=13 March 2011}}</ref>

<ref name="sciam">{{cite web |url=http://www.scientificamerican.com/article.cfm?id=kepler-planet-census|title=Kepler Spacecraft Shows That Smaller Planets Abound|date=2011|publisher=[[Scientific American]]|access-date=2011-05-26}}</ref>

<ref name="NASANews">{{cite web |url=http://www.nasa.gov/topics/universe/features/rocky_planet.html |title=NASA'S Kepler Mission Discovers Its First Rocky Planet |date=2011-01-10 |publisher=NASA |access-date=2011-01-10 |archive-date=2015-06-27 |archive-url=https://web.archive.org/web/20150627200219/http://www.nasa.gov/topics/universe/features/rocky_planet.html |url-status=dead }}</ref>

<!---
<ref name="Fogtmann-Schulz">{{cite journal |arxiv=1311.6336|title= Accurate parameters of the oldest known rocky-exoplanet hosting system: Kepler-10 revisited |date=2013-11-26 | doi=10.1088/0004-637X/781/2/67 |volume=781 |journal=The Astrophysical Journal |page=67 |bibcode=2014ApJ...781...67F}}</ref>
--->
<ref name="SIMBAD">{{cite simbad|title=Kepler-10|access-date=2011-02-01}}</ref>

<ref name="harps">{{cite journal |arxiv=1405.7881 |doi=10.1088/0004-637X/789/2/154|title=The Kepler-10 Planetary System Revisited by Harps-N: A Hot Rocky World and a Solid Neptune-Mass Planet|journal=The Astrophysical Journal|volume=789|issue=2|pages=154|year=2014|last1=Dumusque|first1=Xavier|last2=Bonomo|first2=Aldo S.|last3=Haywood|first3=Raphaëlle D.|last4=Malavolta|first4=Luca|last5=Ségransan|first5=Damien|last6=Buchhave|first6=Lars A.|last7=Cameron|first7=Andrew Collier|last8=Latham|first8=David W.|last9=Molinari|first9=Emilio|last10=Pepe|first10=Francesco|last11=Udry|first11=Stéphane|last12=Charbonneau|first12=David|last13=Cosentino|first13=Rosario|last14=Dressing|first14=Courtney D.|last15=Figueira|first15=Pedro|last16=Fiorenzano|first16=Aldo F. M.|last17=Gettel|first17=Sara|last18=Harutyunyan|first18=Avet|last19=Horne|first19=Keith|last20=Lopez-Morales|first20=Mercedes|last21=Lovis|first21=Christophe|last22=Mayor|first22=Michel|last23=Micela|first23=Giusi|last24=Motalebi|first24=Fatemeh|last25=Nascimbeni|first25=Valerio|last26=Phillips|first26=David F.|last27=Piotto|first27=Giampaolo|last28=Pollacco|first28=Don|last29=Queloz|first29=Didier|last30=Rice|first30=Ken|display-authors=15|bibcode=2014ApJ...789..154D|s2cid=53475787}}</ref>

<ref name="Weiss2016">{{cite journal |last1=Weiss |first1=Lauren M. |last2=Rogers |first2=Leslie A. |display-authors=etal |date=March 2016 |title=Revised Masses and Densities of the Planets around Kepler-10 |journal=[[The Astrophysical Journal]] |volume=819 |issue=1 |pages=83 |doi=10.3847/0004-637X/819/1/83 |arxiv=1601.06168 |bibcode=2016ApJ...819...83W |doi-access=free }}</ref>

<ref name=Rajpaul>{{citation | first=V. | last=Rajpaul |date=July 2017 | title=Pinning down the mass of Kepler-10c: the importance of sampling and model comparison | journal=Monthly Notices of the Royal Astronomical Society | volume=471 | issue=1 | pages=L25–L130 | bibcode=2017MNRAS.471L.125R | doi=10.1093/mnrasl/slx116 | doi-access=free | postscript=. |arxiv = 1707.06192 }}</ref>

<ref name="Bonomo2023">{{cite journal |last1=Bonomo |first1=A. S. |last2=Dumusque |first2=X. |display-authors=etal |date=April 2023 |title=Cold Jupiters and improved masses in 38 Kepler and K2 small-planet systems from 3661 high-precision HARPS-N radial velocities. No excess of cold Jupiters in small-planet systems |journal=[[Astronomy & Astrophysics]] |volume= |issue= |pages= |doi= 10.1051/0004-6361/202346211|arxiv=2304.05773|s2cid=258078829 }}</ref>

}}

{{Kepler-10}}
{{Stars of Draco}}
{{2011 in space}}

{{Sky|19|02|43|+|50|14|28.7}}

{{DEFAULTSORT:Kepler-10}}
[[Category:Kepler-10| ]]
[[Category:G-type main-sequence stars]]
[[Category:Planetary systems with three confirmed planets]]
[[Category:Draco (constellation)]]
[[Category:Kepler objects of interest|0072]]
[[Category:Planetary transit variables]]