Gamma Centauri

{{about-distinguish|γ Centauri|HIP 70969{{!}}Y Centauri|HD 120987{{!}}y Centauri}}

{{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}}

| dec = {{DEC|−48|57|35.5375}}

| appmag_v = +2.17 (+2.85/+2.95)

| constell = Centaurus

}}

{{Starbox character

| class = A1IV+ {{nowrap|(A1IV + A0IV)}}

| b-v = −0.01

| u-b = −0.01

| variable =

}}

{{Starbox astrometry

| radial_v = −5.5

| prop_mo_ra = −185.72

| prop_mo_dec = +5.79

| parallax = 25.06

| p_error = 0.28

| parallax_footnote =

| absmag_v = −0.81

}}

{{Starbox orbit

| reference =

| name=γ Centauri B

| 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|1,931.25 ± 0.07}}

| periarg = {{val|187.9|1.5}}

}}

{{Starbox detail

| source = {{Cite web |title=Muhlifain |url=http://stars.astro.illinois.edu/sow/muhlifain.html |access-date=2025-02-06 |website=stars.astro.illinois.edu}}

| component1 = A

| mass = 2.8

| radius = {{solar radius calculator|type=LT|95|9300|decimals=1}}{{efn|name=radius}}

| luminosity = 95

| temperature = 9,300

| gravity = 3.52

| metal = −0.29

| 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, Gam 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

}}

Gamma Centauri, Latinized from γ Centauri, is a binary star system in the southern constellation of Centaurus. It has the proper name Muhlifain,{{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}} not to be confused with Muliphein, which is γ Canis Majoris; both names derive from the same Arabic root. The system is visible to the naked eye as a single point of light with a combined apparent visual magnitude of +2.17; individually they are third-magnitude stars.

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°. 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. At the distance of this system, this is equivalent to a physical separation of about {{val|93|ul=AU}}.

The combined stellar classification of the pair is A1IV+; when they are separated out they have individual classes of A1IV and A0IV, suggesting they are A-type subgiant stars in the process of becoming giants. The star Tau Centauri is relatively close to Gamma Centauri, with an estimated separation of {{convert|1.72|ly|pc|abbr=off}}. There is a 98% chance that they are co-moving stars.

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, ξ¹ Centauri, τ Centauri, D Centauri and σ Centauri.{{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}}. 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}}).{{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.

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").{{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}}

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: $\sqrt{\biggl(\frac{5,772}{9,300}\biggr)^4 \cdot 95} = 3.8\ R_\odot.$ }}

}}

References

{{reflist|30em|refs=

{{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 }}

{{cite book | last=Evans | first=D. S. | date=June 20–24, 1966 | editor1=Batten, Alan Henry |editor2=Heard, John Frederick | title=The Revision of the General Catalogue of Radial Velocities | work=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 | volume=30 | page=57 | location=University of Toronto | publisher=International Astronomical Union | bibcode=1967IAUS...30...57E }}

{{cite journal | display-authors=1 | last1=Gray | first1=R. O. | last2=Corbally | first2=C. J. | last3=Garrison | first3=R. F. | last4=McFadden | first4=M. T. | last5=Bubar | first5=E. J. | last6=McGahee | first6=C. E. | last7=O'Donoghue | first7=A. A. | last8=Knox | first8=E. R. | title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample | journal=The Astronomical Journal | volume=132 | issue=1 | pages=161–170 |date=July 2006 | doi=10.1086/504637 | bibcode=2006AJ....132..161G |arxiv = astro-ph/0603770 | s2cid=119476992 }}

{{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 }}

{{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 }}

{{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 }}

{{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 }}

{{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 }}

{{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 }}

{{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 }}

{{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