{{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 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 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 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 types of A1IV and A0IV,<ref name=Gray_Garrison_1987/> suggesting they are A-type subgiant stars in the process of becoming 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 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 ''Arsenal'', refers to an asterism consisting of γ Centauri, ζ Centauri, η Centauri, θ Centauri, 2 Centauri, HD 117440, 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 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 Aranda and Luritja tribe around Hermannsburg, Central Australia named a quadrangular arrangement comprising this star, δ Cen (Ma Wei), 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 solar nominal effective temperature of 5,772 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 Centauri, Gamma BD-48 7597 110304 061932 4819 Category:Brightest stars