Star in the constellation Centaurus
Gamma Centauri Location of γ Centauri (circled)
Observation dataEpoch J2000 Equinox J2000 Constellation Centaurus Right ascension 12h 41m 31.04008s [ 1] Declination −48° 57′ 35.5375″[ 1] Apparent magnitude (V)+2.17[ 2] [ 3] Characteristics Spectral type A1IV+[ 4] (A1IV + A0IV) [ 5] U−Bcolor index −0.01[ 2] B−Vcolor index −0.01[ 2] Astrometry Radial velocity (Rv )−5.5[ 6] km/s Proper motion (μ)RA: −185.72[ 1] mas /yr Dec.: +5.79[ 1] mas /yr Parallax (π)25.06± 0.28 mas [ 1] Distance 130 ± 1 ly pc ) Absolute magnitude (MV )−0.81[ 7] Orbit [ 8] Companion γ Centauri B Period (P)± 0.21yr Semi-major axis (a)± 0.011Eccentricity (e)± 0.003Inclination (i)± 0.7Longitude of the node (Ω)± 0.7Periastron epoch (T)1931.25 ± 0.07 Argument of periastron (ω)± 1.5Details[ 9] Mass 2.8 M ☉ Radius 3.8[ a] R ☉ Luminosity 95 L ☉ Surface gravity (log g )3.52[ 4] cgs Temperature 9,300 K Metallicity −0.29[ 4] B Mass 2.8 M ☉ Radius 3.8[ a] R ☉ Luminosity 95 L ☉ Temperature 9,300 K Other designations Muhlifain,γ Cen ,CD −48°7597GC 17262HD 110304HIP 61932HR 4819SAO 223603CCDM J12415-4858WDS 12415-4858 Database references SIMBAD data
Gamma Centauri is abinary star system in thesouthern constellation ofCentaurus , which is probably part of a wider system together withTau Centauri . The system is visible to the naked eye as a single point of light with a combinedapparent visual magnitude of +2.17;[ 2] [ 3]
Its main name is aBayer designation that isLatinized from γ Centauri, and abbreviated Gamma Cen or γ Cen.
It has the proper nameMuhlifain ,[ 10] γ Canis Majoris ; both names derive from the same Arabic root.
This system is located at a distance of about 130light-years (40parsecs ) from theSun based onparallax . In 2000, the pair had an angular separation of 1.217arcseconds with aposition angle of 351.9°.[ 3] orbital period of 84.5 years and asemimajor axis of 0.93 arcsecond.[ 11] [ 8] AU [ 9]
The stars havespectral types of A1IV and A0IV,[ 5] A-type subgiant stars in the process of becominggiants . The stars have similar characteristics, with an estimated 2.8 times theSun's mass , around 100 times theSun's luminosity and an estimatedeffective temperature of 9,300 K.[ 9]
The starTau Centauri very likely makes a widely-separated binary system with Gamma Centauri, it is aco-moving star with an estimated separation of 1.72 light-years (0.53 parsecs). There is a 98% chance that they are gravitationally bound.[ 12]
InChinese astronomy ,庫樓 Kù Lóu Arsenal asterism consisting of γ Centauri,ζ Centauri ,η Centauri ,θ Centauri ,2 Centauri ,HD 117440 ,ξ1 Centauri ,τ Centauri ,D Centauri andσ Centauri .[ 13] Chinese name for γ Centauri itself is庫樓七 Kù Lóu qī the Seventh Star of Arsenal ).[ 14]
The people ofAranda andLuritja tribe aroundHermannsburg ,Central Australia named a quadrangular arrangement comprising this star,δ Cen (Ma Wei),δ Cru (Imai) and γ Cru (Gacrux ) asIritjinga ("The Eagle-hawk").[ 15]
^a b c d e van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction".Astronomy and Astrophysics .474 (2):653– 664.arXiv :0708.1752 Bibcode :2007A&A...474..653V .doi :10.1051/0004-6361:20078357 .S2CID 18759600 . ^a b c d Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars".Communications of the Lunar and Planetary Laboratory .4 (99): 99.Bibcode :1966CoLPL...4...99J . ^a b c Fabricius, C.; Makarov, V. V. (April 2000). "Two-colour photometry for 9473 components of close Hipparcos double and multiple stars".Astronomy and Astrophysics .356 :141– 145.Bibcode :2000A&A...356..141F . ^a b c Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample".The Astronomical Journal .132 (1):161– 170.arXiv :astro-ph/0603770 Bibcode :2006AJ....132..161G .doi :10.1086/504637 .S2CID 119476992 . ^a b Gray, R. O.; Garrison, R. F. (December 1987)."The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation" .Astrophysical Journal Supplement .65 : 581.Bibcode :1987ApJS...65..581G .doi :10.1086/191237 ^ Evans, D. S. (June 20–24, 1966). Batten, Alan Henry; Heard, John Frederick (eds.). "The Revision of the General Catalogue of Radial Velocities".Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium No. 30 .30 . University of Toronto:International Astronomical Union : 57.Bibcode :1967IAUS...30...57E . ^ Schaaf, Fred (2008).The brightest stars: discovering the universe through the sky's most brilliant stars .John Wiley and Sons . p. 262.Bibcode :2008bsdu.book.....S .ISBN 978-0-471-70410-2 ^a b Argyle, R. W.; et al. (May 2015)."Micrometric measures and orbits of southern visual double stars" .Astronomische Nachrichten .336 (4):378– 387.Bibcode :2015AN....336..378A .doi :10.1002/asna.201412166 ^a b c Kaler, James B."MUHLIFAIN (Gamma Centauri)" .Stars .University of Illinois . Retrieved2011-12-31 . ^ Paul Kunitzsch (1959).Arabische Sternnamen in Europa, von Paul Kunitzsch ^ Mason, Brian D.; et al. (December 2001)."The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog" .The Astronomical Journal .122 (6):3466– 3471.Bibcode :2001AJ....122.3466M .doi :10.1086/323920 ^ Shaya, Ed J.; Olling, Rob P. (January 2011). "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue".The Astrophysical Journal Supplement .192 (1): 2.arXiv :1007.0425 Bibcode :2011ApJS..192....2S .doi :10.1088/0067-0049/192/1/2 .S2CID 119226823 . ^ (in Chinese) 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 ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived January 30, 2011, at theWayback Machine , Hong Kong Space Museum. Accessed online November 23, 2010.^ Raymond Haynes; Roslynn D. Haynes; David Malin; Richard McGee (1996),Explorers of the Southern Sky: A History of Australian Astronomy ISBN 978-0-521-36575-8
