{{Short description|Star in the constellation Centaurus}} {{about-distinguish|γ Centauri|HIP 70969{{!}}Y Centauri|HD 120987{{!}}y Centauri}} {{Starbox begin}} {{Starbox image | image = {{Location mark | image=Centaurus IAU.svg | float=center | width=240 | position=right | mark=Red circle.svg | mark_width=10 | mark_link=γ Cen | x%=53.6 | y%=51.0 }} | caption=Location of γ Centauri (circled) }} {{Starbox observe | epoch = J2000 | ra = {{RA|12|41|31.04008}}<ref name=aaa474_2_653/> | dec = {{DEC|−48|57|35.5375}}<ref name=aaa474_2_653/> | appmag_v = +2.17<ref name=clpl4_99/> (+2.84/+2.94)<ref name=aaa356_141/> | constell = [[Centaurus]] }} {{Starbox character | component1 = A | type = [[subgiant]]<ref name=kaler/> | class = A1IV<ref name=Gray_Garrison_1987/> | b-v = −0.03<ref name=marecki1994/> | u-b = 0.00<ref name=marecki1994/> | variable = | component2 = B | type2 = [[subgiant]]<ref name=kaler/> | class2 = A0IV<ref name=Gray_Garrison_1987/> | b-v2 = +0.01<ref name=marecki1994/> | u-b2 = −0.02<ref name=marecki1994/> | variable2 = }} {{Starbox astrometry | radial_v = −5.5<ref name=rgcrv/> | prop_mo_ra = −185.72<ref name=aaa474_2_653/> | prop_mo_dec = +5.79<ref name=aaa474_2_653/> | parallax = 25.06 | p_error = 0.28 | parallax_footnote = <ref name=aaa474_2_653/> | absmag_v = −0.81<ref name=schaaf/> }} {{Starbox orbit | reference = <ref name=Argyle_et_al_2015/> | period = {{val|83.57|0.21}} | axis = {{val|0.869|0.011}} | eccentricity = {{val|0.793|0.003}} | inclination = {{val|113.7|0.7}} | node = {{val|2.6|0.7}} | periastron = {{nowrap|1931.25 ± 0.07}} | periarg = {{val|187.9|1.5}} }} {{Starbox detail | source = <ref name=kaler/> | mass = 2.8 | radius = {{solar radius calculator|type=LT|95|9300|decimals=1}}{{efn|name=radius}} | luminosity = 95 | temperature = 9,300 | rotational_velocity = | age = | component2 = B | mass2 = 2.8 | radius2 = {{solar radius calculator|type=LT|95|9300|decimals=1}}{{efn|name=radius}} | luminosity2 = 95 | temperature2 = 9,300 }} {{Starbox catalog | names = {{odlist | name=Muhlifain | B=γ Cen | HR=4819 | HD=110304 | CD=−48°7597 | SAO=223603 | WDS=12415-4858 | HIP=61932 | GC=17262 | CCDM=J12415-4858 }} }} {{Starbox reference | Simbad=HD+110304 | Simbad2=Gamma+Cen+A |sn2=A | Simbad3=Gamma+Cen+B |sn3=B }} {{Starbox end}}
'''Gamma Centauri''' is a [[binary star]] system in the [[Southern celestial hemisphere|southern]] [[constellation]] of [[Centaurus]], which is probably part of a wider system together with [[Tau Centauri]]. The system is visible to the naked eye as a single point of light with a combined [[apparent visual magnitude]] of +2.17;<ref name=clpl4_99/> individually they are third-magnitude stars.<ref name=aaa356_141/>
==Nomenclature== Its main name is a [[Bayer designation]] that is [[Romanization of Greek|Latinized]] from γ Centauri, and abbreviated Gamma Cen or γ Cen.
It has the proper name '''Muhlifain''',<ref>{{cite book|author=Paul Kunitzsch|title=Arabische Sternnamen in Europa, von Paul Kunitzsch|url=https://books.google.com/books?id=qhtGQwAACAAJ|year=1959|page=188|publisher=O. Harrassowitz}}</ref> not to be confused with Muliphein, which is [[γ Canis Majoris]]; both names derive from the same Arabic root.
==Characteristics== This system is located at a distance of about {{Convert|130|ly|pc|abbr=off|lk=on}} from the [[Sun]] based on [[Stellar parallax|parallax]]. In 2000, the pair had an angular separation of 1.217 [[arcseconds]] with a [[position angle]] of 351.9°.<ref name="aaa356_141" /> Their positions have been observed since 1897, which is long enough to estimate an [[orbital period]] of 84.5 years and a [[semimajor axis]] of 0.93 arcsecond.<ref name="aj122_6_3466" /><ref name="Argyle_et_al_2015" /> At the distance of this system, this is equivalent to a physical separation of about {{val|93|ul=AU}}.<ref name="kaler" />
The stars have [[spectral type]]s of A1IV and A0IV,<ref name=Gray_Garrison_1987/> suggesting they are [[A-type star|A-type]] [[subgiant]] stars in the process of becoming [[giant star|giants]]. The stars have similar characteristics, with an estimated 2.8 times the [[Sun's mass]], around 100 times the [[Sun's luminosity]] and an estimated [[effective temperature]] of 9,300 K.<ref name=kaler/>
The star [[Tau Centauri]] very likely makes a widely-separated binary system with Gamma Centauri, it is a [[Comoving and proper distances|co-moving star]] with an estimated separation of {{convert|1.72|ly|pc|abbr=off}}. There is a 98% chance that they are gravitationally bound.<ref name=apjs192_1_2/>
==Etymology==
In [[Chinese astronomy]], {{lang|zh|庫樓}} ({{lang|zh-Latn|Kù Lóu}}), meaning ''[[Horn (Chinese constellation)|Arsenal]]'', refers to an [[Asterism (astronomy)|asterism]] consisting of γ Centauri, [[ζ Centauri]], [[η Centauri]], [[θ Centauri]], [[2 Centauri]], [[HD 117440]], [[Xi1 Centauri|ξ<sup>1</sup> Centauri]], [[τ Centauri]], [[D Centauri]] and [[σ Centauri]].<ref>{{in lang|zh}} ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}.</ref> Consequently, the [[Chinese star names|Chinese name]] for γ Centauri itself is {{lang|zh|庫樓七}} ({{lang|zh-Latn|Kù Lóu qī}}, {{langx|en|the Seventh Star of Arsenal}}).<ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_m.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive |url=https://web.archive.org/web/20110130063012/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_m.htm |date=January 30, 2011 }}, Hong Kong Space Museum. Accessed online November 23, 2010.</ref>
The people of [[Arrernte people|Aranda]] and [[Luritja]] tribe around [[Hermannsburg, Northern Territory|Hermannsburg]], [[Central Australia]] named a quadrangular arrangement comprising this star, [[Delta Centauri|δ Cen]] (Ma Wei), [[Imai (star)|δ Cru]] (Imai) and γ Cru ([[Gacrux]]) as ''Iritjinga'' ("The Eagle-hawk").<ref>{{citation|author1=Raymond Haynes|author2=Roslynn D. Haynes|author3=David Malin|author4=Richard McGee|title=Explorers of the Southern Sky: A History of Australian Astronomy|url=https://books.google.com/books?id=XoeiJxMmXZ8C|year=1996|publisher=Cambridge University Press|location=Cambridge|isbn=978-0-521-36575-8|page=8}}</ref>
==Notes== {{Notelist|notes=
{{Efn|name=radius|1=Calculated, using the [[Stefan-Boltzmann law]] and the star's [[effective temperature]] and luminosity, with respect to the [[Sun|solar]] nominal effective temperature of 5,772 [[Kelvin|K]]:<math display="block">\sqrt{\biggl(\frac{5,772}{9,300}\biggr)^4 \cdot 95} = 3.8\ R_\odot.</math>}}
}}
== References == {{reflist|30em|refs=
<ref name=marecki1994>{{cite journal |last1=Marecki |first1=A. |last2=Strobel |first2=J. |last3=Strobel |first3=A. |title=VizieR Online Data Catalog: Catalogue of stellar abundances (Marecki+ 1986) |journal=Vizier Online Data Catalog |date=1994 |bibcode=1994yCat.3121....0M }}</ref>
<ref name=aaa474_2_653>{{cite journal | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600 }}</ref>
<ref name="rgcrv">{{Cite journal |last=Evans |first=D. S. |date=June 20–24, 1966 |title=The Revision of the General Catalogue of Radial Velocities |location=University of Toronto |publisher=[[International Astronomical Union]] |volume=30 |page=57 |bibcode=1967IAUS...30...57E |editor-last1=Batten |editor-first1=Alan Henry |editor-last2=Heard |editor-first2=John Frederick |journal=Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium No. 30}}</ref>
<ref name=apjs192_1_2>{{cite journal | last1=Shaya | first1=Ed J. | last2=Olling | first2=Rob P. | title=Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue | journal=The Astrophysical Journal Supplement | volume=192 | issue=1 | page=2 |date=January 2011 | doi=10.1088/0067-0049/192/1/2 | bibcode=2011ApJS..192....2S |arxiv = 1007.0425 | s2cid=119226823 }}</ref>
<ref name=aaa356_141>{{cite journal | last1=Fabricius | first1=C. | last2=Makarov | first2=V. V. | title=Two-colour photometry for 9473 components of close Hipparcos double and multiple stars | journal=Astronomy and Astrophysics | volume=356 | pages=141–145 |date=April 2000 | bibcode=2000A&A...356..141F }}</ref>
<ref name=clpl4_99>{{Cite journal | last1=Johnson | display-authors=1 | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | date=1966 | bibcode=1966CoLPL...4...99J }}</ref>
<ref name=schaaf>{{cite book | first1=Fred | last1=Schaaf | title=The brightest stars: discovering the universe through the sky's most brilliant stars | publisher=[[John Wiley and Sons]] | date=2008 | isbn=978-0-471-70410-2 | page=262 | bibcode=2008bsdu.book.....S }}</ref>
<ref name=aj122_6_3466>{{cite journal | display-authors=1 | last1=Mason | first1=Brian D. | last2=Wycoff | first2=Gary L. | last3=Hartkopf | first3=William I. | last4=Douglass | first4=Geoffrey G. | last5=Worley | first5=Charles E. | title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog | journal=The Astronomical Journal | volume=122 | issue=6 | pages=3466–3471 |date=December 2001 | doi=10.1086/323920 | bibcode=2001AJ....122.3466M | doi-access=free }}</ref>
<ref name=kaler>{{cite web | first1=James B. | last1=Kaler | title=MUHLIFAIN (Gamma Centauri) | work=Stars | publisher=[[University of Illinois]] | url=http://stars.astro.illinois.edu/sow/muhlifain.html | access-date=2011-12-31 }}</ref>
<ref name=Gray_Garrison_1987>{{cite journal | title=The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation | last1=Gray | first1=R. O. | last2=Garrison | first2=R. F. | journal=Astrophysical Journal Supplement | volume=65 | page=581 | date=December 1987 | doi=10.1086/191237 | bibcode=1987ApJS...65..581G | doi-access=free }}</ref>
<ref name=Argyle_et_al_2015>{{cite journal | title=Micrometric measures and orbits of southern visual double stars | display-authors=1 | last1=Argyle | first1=R. W. | last2=Alzner | first2=A. | last3=van Leeuwen | first3=F. | journal=Astronomische Nachrichten | volume=336 | issue=4 | pages=378–387 | date=May 2015 | doi=10.1002/asna.201412166 | bibcode=2015AN....336..378A | doi-access=free }}</ref>
}}
{{Stars of Centaurus}}
<!-- Properties --> [[Category:A-type subgiants]] [[Category:Binary stars]] <!-- Other --> [[Category:Centaurus]] [[Category:Bayer objects|Centauri, Gamma]] [[Category:Durchmusterung objects|BD-48 7597]] [[Category:Henry Draper Catalogue objects|110304]] [[Category:Hipparcos objects|061932]] [[Category:Bright Star Catalogue objects|4819]] [[Category:Brightest stars]]