编辑“︁XO-2”︁

{{Starbox begin
| name = XO-2
}}
{{Starbox observe
| epoch = 2000
| constell = [[天猫座]]  <ref name="Roman1987"/>
| ra = {{RA|07|48|06.468}}<ref name="Høg2000"/>
| dec = {{DEC|+50|13|32.96}}<ref name="Høg2000"/>
| appmag_v = 11.18 ± 0.03<ref name="Burke2007"/> 
}}
{{Starbox character
| class = ? + K0V
}}
{{Starbox astrometry
| radial_v =  
| prop_mo_ra = -34.7 ± 2.6<ref name="Høg2000"/> 
| prop_mo_dec = -153.6 ± 2.4<ref name="Høg2000"/>
| dist_ly = {{convert|148|+/-|10|pc|ly|disp=output number only}}<ref name="Torres2008"/>
| dist_pc = 148 ± 10<ref name="Torres2008"/> 
}}
{{Starbox detail
| component1 = XO-2 S
| mass = 0.982 ± 0.034<ref name="Desidera2014"/>
| radius = 1.02<ref name="Desidera2014"/>
| gravity =
| luminosity = 
| temperature = 5399 ± 55 <ref name="Desidera2014"/>
| metal_fe = 0.39 ± 0.05<ref name="Desidera2014"/>
| rotation = 
| age_gyr = 7.1 ± {{±|2.5|2.9}}<ref name="Desidera2014"/>
| component2 = XO-2 N
| class2 = K0V
| mass2 = 0.971 ± 0.034<ref name="Fernandez2009"/>
| radius2 = 0.976{{±|0.024|0.016}}<ref name="Fernandez2009"/>
| gravity2 =
| luminosity2 = 
| temperature2 = 5340 ± 32<ref name="Burke2007"/>
| metal_fe2 = 0.44 ± 0.02<ref name="Burke2007"/> 
| rotation2 = 
| age_gyr2 = 6.3 ± 2.4<ref name="Fernandez2009"/> 
}}
{{Starbox catalog 
| names = [[依巴谷星表|TYC]] 3413-5-1，[[导航星表|GSC]] 03413-00005，[[2微米全天巡天|2MASS]] J07480647+5013328，ASCC 251428，LSPM J0748+5013N，USNO-B1.0 1402-00191767 
}}
{{Starbox reference |
| Simbad=TYC3413-5-1
| EPE=XO-2
}}
{{Starbox end}}
'''XO-2'''是一個位于[[天猫座]]的[[聯星]]系統，兩颗成員星都是与太阳类似而温度略低的[[恒星]]，距地球大约{{convert|148|pc|ly|disp=output number only}}[[光年]]<ref name="Torres2008"/> 。該系統的兩顆成員星分別為 '''XO2-S'''（或 '''XO-2A'''）和 '''XO2-N'''（或 '''XO-2B'''）<ref name="Desidera2014"/>。它的[[星等|视星等]]只有11等，因此地球上用肉眼无法看到，但是使用小型[[望远镜]]既可观测到。这颗恒星也因为它较大的[[自行]]而引人注目<ref name="SIMBAD"/>。
 
XO-2N 和 XO-2S 兩者距離約{{formatnum:4600}}[[天文單位]]<ref name="Burke2007"/>。

== 行星系统 ==
XO-2N拥有一颗已知的[[太阳系外行星]]—[[XO-2b|XO-2Nb]]（偶爾被稱為 XO-2Bb），是[[热木星]]。该行星是通过使用[[系外行星侦测法#凌日法|凌日法]]借助位于美国[[夏威夷]][[茂宜岛]]的[[XO望远镜]]于2007年发现的<ref name="Burke2007"/>。

2014年時天文學家宣布在 XO-2S 旁發現兩顆系外行星，其中一顆質量與木星相若，另一顆則相當於土星<ref name="Desidera2014"/>。

該聯星系中兩顆恆星都有[[徑向速度]]變化趨勢被觀測到，這也許是另一顆長週期類木行星或棕矮星存在的證據。

{{OrbitboxPlanet begin  |name=XO-2S
| table_ref = <ref name="Desidera2014"/>
}} 
{{OrbitboxPlanet
| exoplanet = [[XO-2Sb|b]]
| mass = ≥ 0.259 ± 0.014
| period = 18.157 ± 0.034
| semimajor = 0.1344 ±0.0025 
| eccentricity = 0.18 ± 0.035
}} 
{{OrbitboxPlanet
| exoplanet = [[XO-2Sc|c]]
| mass = ≥ 1.37 ± 0.053
| period = 120.8 ± 0.034
| semimajor = 0.4756 ±0.0087 
| eccentricity =0.1528 ± 0.01
}} 
{{Orbitbox end}}

{{OrbitboxPlanet begin  |name=XO-2N
| table_ref = <ref name="Narita2011"/><ref name="Sing2011"/>
}} 
{{OrbitboxPlanet
| exoplanet = [[XO-2b|b]]
| mass = 0.62 ± 0.02
| radius = 0.973 ± 0.03
| period = 2.61586178 ± 0.00000075 
| semimajor = 0.0369 ±0.002 
| eccentricity = 0.045 ± 0.024
| inclination = 88.7 ± 1.3
}} 
{{Orbitbox end}}

== 参见 ==
* [[HD 20781]]和[[HD 20782]]
* [[XO望远镜]]
* [[确定存在的太阳系外行星列表]]

== 参考资料 ==
{{Reflist|colwidth=30em|refs=

<ref name="Burke2007">{{cite journal | title=XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary | url=http://iopscience.iop.org/0004-637X/671/2/2115/fulltext/ | last1=Burke | first1=Christopher J. | last2=McCullough | first2=P. R. | last3=Valenti | first3=Jeff A. | last4=Johns‐krull | first4=Christopher M. | last5=Janes | first5=Kenneth A. | last6=Heasley | first6=J. N. | last7=Summers | first7=F. J. | last8=Stys | first8=J. E. | last9=Bissinger | first9=R. | display-authors=1 | journal=The Astrophysical Journal | year=2007 | volume=671 | issue=2 | pages=2115–2128 | arxiv=0705.0003 | bibcode=2007ApJ...671.2115B | doi=10.1086/523087 | access-date=2012-01-11 | archive-date=2014-06-28 | archive-url=https://web.archive.org/web/20140628193204/http://iopscience.iop.org/0004-637X/671/2/2115/fulltext/ | dead-url=no }}</ref>

<ref name="Fernandez2009">{{cite journal | title=The Transit Light Curve Project. XII. Six Transits of the Exoplanet XO-2b | url=http://iopscience.iop.org/1538-3881/137/6/4911/fulltext/ | last1=Fernandez | first1=Jose M. | last2=Holman | first2=Matthew J. | last3=Winn | first3=Joshua N. | last4=Torres | first4=Guillermo | last5=Shporer | first5=Avi | last6=Mazeh | first6=Tsevi | last7=Esquerdo | first7=Gilbert A. | last8=Everett | first8=Mark E. | display-authors=1 | journal=The Astronomical Journal | year=2009 | volume=137 | issue=6 | pages=4911–4916 | arxiv=0903.2687 | bibcode=2009AJ....137.4911F | doi=10.1088/0004-6256/137/6/4911 }}</ref>

<ref name="Høg2000">{{cite journal | url=http://articles.adsabs.harvard.edu/full/2000A%26A...355L..27H | title=The Tycho-2 catalogue of the 2.5 million brightest stars | last1=Høg | first1=E. | last2=Fabricius | first2=C. | last3=Makarov | first3=V. V. | last4=Urban | first4=S. | last5=Corbin | first5=T. | last6=Wycoff | first6=G. | last7=Bastian | first7=U. | last8=Schwekendiek | first8=P. | last9=Wicenec | first9=A. | display-authors=1 | journal=Astronomy and Astrophysics | volume=355 | pages=L27–L30 | year=2000 | bibcode=2000A&A...355L..27H | access-date=2014-07-08 | archive-date=2015-11-07 | archive-url=https://web.archive.org/web/20151107111237/http://articles.adsabs.harvard.edu/full/2000A%26A...355L..27H | dead-url=no }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-S?TYC%203413-5-1 Vizier catalog entry ] {{Wayback|url=http://vizier.u-strasbg.fr/viz-bin/VizieR-S?TYC%203413-5-1 |date=20160304041126 }}</ref>

<ref name="Narita2011">{{cite journal | title=XO-2b: a Prograde Planet with a Negligible Eccentricity and an Additional Radial Velocity Variation | last1=Narita | first1=Norio | last2=Hirano | first2=Teruyuki | last3=Sato | first3=Bun’ei | last4=Harakawa | first4=Hiroki | last5=Fukui | first5=Akihiko | last6=Aoki | first6=Wako | last7=Tamura | first7=Motohide | display-authors=1 | journal=Publications of the Astronomical Society of Japan | year=2011 | volume=63 | issue=6 | pages=L67–L71 | arxiv=1110.6136 | bibcode=2011PASJ...63L..67N | doi=10.1093/pasj/63.6.l67}}</ref>

<ref name="Roman1987">{{cite journal | title=Identification of a Constellation From a Position | last1=Roman | first1=Nancy G. | journal=Publications of the Astronomical Society of the Pacific | volume=99 | issue=617 | pages=695–699 | year=1987 | bibcode=1987PASP...99..695R | doi=10.1086/132034 }} [http://vizier.u-strasbg.fr/vizier/VizieR/constellations.htx Vizier query form ] {{Wayback|url=http://vizier.u-strasbg.fr/vizier/VizieR/constellations.htx |date=20190717180728 }}</ref>

<ref name="SIMBAD">{{cite web | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=XO-2&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id | title=TYC 3413-5-1 -- High proper-motion Star | publisher=Centre de Données astronomiques de Strasbourg | accessdate=2012-01-15 | archive-date=2014-07-14 | archive-url=https://web.archive.org/web/20140714171013/http://simbad.u-strasbg.fr/simbad/sim-id?Ident=XO-2&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id | dead-url=no }}</ref>

<ref name="Sing2011">{{cite journal | title=Gran Telescopio Canarias OSIRIS transiting exoplanet atmospheric survey: detection of potassium in XO-2b from narrowband spectrophotometry | last1=Sing | first1=D. K. | last2=Désert | first2=J.-M. | last3=Fortney | first3=J. J. | last4=Lecavelier Des Etangs | first4=A. | last5=Ballester | first5=G. E. | last6=Cepa | first6=J. | last7=Ehrenreich | first7=D. | last8=López-Morales | first8=M. | last9=Pont | first9=F. | display-authors=1 | journal=Astronomy and Astrophysics | year=2011 | volume=527 | at=article number A73 | arxiv=1008.4795 | bibcode=2011A&A...527A..73S | doi=10.1051/0004-6361/201015579 }}</ref>

<ref name="Torres2008">{{cite journal | title=Improved Parameters for Extrasolar Transiting Planets | url=http://iopscience.iop.org/0004-637X/677/2/1324/fulltext/ | last1=Torres | first1=Guillermo | last2=Winn | first2=Joshua N. | last3=Holman | first3=Matthew J. | display-authors=1 | journal=The Astrophysical Journal | year=2008 | volume=677 | issue=2 | pages=1324–1342 | arxiv=0801.1841 | bibcode=2008ApJ...677.1324T | doi=10.1086/529429 | access-date=2014-07-08 | archive-date=2020-01-28 | archive-url=https://web.archive.org/web/20200128122512/https://iopscience.iop.org/article/10.1086/529429 | dead-url=no }}</ref>

<ref name="Desidera2014">{{cite web | url=http://arxiv.org/abs/1407.0251 | title=The GAPS programme with HARPS-N@TNG IV: A planetary system around XO-2S | accessdate=2014-07-02 | archive-date=2022-07-05 | archive-url=https://web.archive.org/web/20220705044039/https://arxiv.org/abs/1407.0251 | dead-url=no }}</ref>

}}

== 外部链接 ==
* NASA PlanetQuest: [https://web.archive.org/web/20111212105241/http://planetquest.jpl.nasa.gov/news/Gl436.cfm Planet race heats up: 1 month, 32 discoveries]
* {{cite web
| url=http://media4.obspm.fr/exoplanets/base/etoile.php?nom=XO-2
| title=XO-2
| work=Exoplanets
| accessdate=2009-04-28
| archive-url=https://web.archive.org/web/20160303190408/http://media4.obspm.fr/exoplanets/base/etoile.php?nom=XO-2
| archive-date=2016-03-03
| dead-url=yes
}}

{{Sky|07|48|06.468|+|50|13|32.96|486}}

[[Category:K型主序星]]
[[Category:天猫座]]
[[Category:行星凌变星]]
[[Category:聚星的行星系]]