{{Short description|Star in the constellation Centaurus}} {{confuse|T Centauri}} {{Starbox begin | name = τ Centauri }} {{Starbox image | image = {{Location mark | image=Centaurus constellation map.svg | float=center | width=280 | position=right | mark=Red circle.svg | mark_width=10 | mark_link=τ Cen | x=710 | y=600 }} | caption = Location of τ Centauri (circled) }} {{Starbox observe | epoch = [[J2000.0]] | equinox = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Centaurus]]<ref name=Anderson2012/> | ra = {{RA|12|37|42.164}}<ref name=GaiaDR3/> | dec = {{DEC|−48|32|28.70}}<ref name=GaiaDR3/> | appmag_v = +3.86<ref name=Mermilliod1986/> }} {{Starbox character | type = | class = A0 V<ref name=Lagrange2009/> or A1 IVnn<ref name=Gray2003/> | b-v = +0.06<ref name=Mermilliod1986/> | u-b = +0.04<ref name=Mermilliod1986/> | r-i = | variable = }} {{Starbox astrometry | radial_v = {{Val|+5.5|2.3}}<ref name=deBruijne2012/> | prop_mo_ra = −186.081 | prop_mo_dec = −6.757 | pm_footnote = <ref name=GaiaDR3/> | parallax = 24.2953 | p_error = 0.53 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = +0.83<ref name=Anderson2012/> }} {{Starbox detail | source = | mass = 2.31<ref name=David2015/> | radius = 2.7<ref name=tycho-gaia/> | luminosity = 39<ref name=tycho-gaia/> | temperature = {{Val|10533|358|fmt=commas}}<ref name=David2015/> | gravity = {{Val|4.02|0.14}}<ref name=David2015/> | metal_fe = | rotational_velocity = {{Val|296.8|3.8}}<ref name=Diaz2011/> | age_myr = 132<ref name=David2015/> }} {{Starbox catalog | names = {{odlist | B=τ Cen | CD=−47°7745 | HD=109787 | HIP=61622 | HR=4802 | SAO=223560 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = tau+Cen }} {{Starbox end}} '''Tau Centauri''' is a solitary<ref name=DeRosa2014/> [[star]] in the southern [[constellation]] of [[Centaurus]]. Its name is a [[Bayer designation]] that is [[Romanization of Greek|Latinized]] from τ Centauri, and abbreviated Tau Cen or τ Cen. This star is visible to the naked eye with an [[apparent visual magnitude]] of +3.86.<ref name=Mermilliod1986/> The distance to this star, based upon an annual [[stellar parallax|parallax shift]] of {{Val|24.3|ul=mas}},<ref name=GaiaDR3/> is 131 [[light year]]s. It makes a [[star system]] with [[Gamma Centauri]] at 98% probability, both separated by {{Convert|0.53|pc|ly|abbr=on|order=flip}}.<ref name=Shaya2011/>
This is an [[A-type star]] with [[stellar classification]]s of A0 V<ref name=Lagrange2009/> or A1 IVnn,<ref name=Gray2003/> indicating it may be a [[main sequence star]] or a more [[stellar evolution|evolved]] [[subgiant star]]. It is around 132 million years old<ref name=David2015/> and is spinning rapidly with a [[projected rotational velocity]] of 296.8 km/s.<ref name=Diaz2011/> This is giving the star an [[Oblate spheroid|oblate]] shape, with an estimated equatorial girth that is 30% larger than the polar radius.<ref name=belle2012/> The star has an estimated 2.3 times the [[solar mass|mass of the Sun]]<ref name=David2015/> and 2.7 times the [[solar radius|Sun's radius]].<ref name=tycho-gaia/>
==References== <references>
<ref name=GaiaDR3>{{Cite Gaia DR3 | 6127688772460862976 | mode=cs2 | postscript=. | access-date=2025-12-30 }}</ref>
<ref name=Anderson2012>{{cite XHIP | 61622 | mode=cs2 | postscript=. | access-date=2025-12-30 }}</ref>
<ref name=belle2012>{{citation | title=Interferometric observations of rapidly rotating stars | last=Belle | first=G. T. | journal=The Astronomy and Astrophysics Review | volume=20| pages=51 | year=2012 | issue=1 | doi=10.1007/s00159-012-0051-2 | bibcode=2012A&ARv..20...51V | arxiv=1204.2572 | s2cid=119273474 | postscript=. }}</ref>
<ref name=deBruijne2012>{{citation | last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C. | title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project | journal=Astronomy & Astrophysics | volume=546 | id=A61 | pages=14 | date=October 2012 | doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D | arxiv=1208.3048 | s2cid=59451347 | postscript=. }}</ref>
<ref name=Gray2003>{{citation | last1=Gray | first1=R. O. | last2=Garrison | first2=R. F. | title=The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation | journal=Astrophysical Journal Supplement Series | volume=70 | issue=4 | pages=623–636 | date=July 1989 | doi=10.1086/191349 | bibcode=1989ApJS...70..623G | postscript=. | doi-access=free }}</ref>
<ref name=tycho-gaia>{{Citation |postscript=. | title=Fundamental parameters and infrared excesses of Tycho-Gaia stars | display-authors=1 | last1=McDonald |first1=I. | last2=Zijlstra |first2=A. A. |last3=Watson |first3=R. A. | journal=Monthly Notices of the Royal Astronomical Society | volume=471 | issue=1 | pages=770–791 | date=October 2017 | doi=10.1093/mnras/stx1433 | doi-access=free | bibcode=2017MNRAS.471..770M | arxiv=1706.02208 | issn=0035-8711}}</ref>
<ref name=Lagrange2009>{{citation | title=Extrasolar planets and brown dwarfs around A-F type stars. VI. High precision RV survey of early type dwarfs with HARPS | display-authors=1 | last1=Lagrange | first1=A.-M. | last2=Desort | first2=M. | last3=Galland | first3=F. | last4=Udry | first4=S. | last5=Mayor | first5=M. | journal=Astronomy and Astrophysics | volume=495 | issue=1 | pages=335–352 | date=February 2009 | doi=10.1051/0004-6361:200810105 | bibcode=2009A&A...495..335L | postscript=. |arxiv = 0809.4636 | s2cid=62894956 }}</ref>
<ref name=Shaya2011>{{citation | 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=DeRosa2014>{{citation | display-authors=1 | last1=De Rosa | first1=R. J. | last2=Patience | first2=J. | last3=Wilson | first3=P. A. | last4=Schneider | first4=A. | last5=Wiktorowicz | first5=S. J. | last6=Vigan | first6=A. | last7=Marois | first7=C. | last8=Song | first8=I. | last9=Macintosh | first9=B. | last10=Graham | first10=J. R. | last11=Doyon | first11=R. | last12=Bessell | first12=M. S. | last13=Thomas | first13=S. | last14=Lai | first14=O. | title=The VAST Survey - III. The multiplicity of A-type stars within 75 pc | journal=Monthly Notices of the Royal Astronomical Society | volume=437 | issue=2 | pages=1216–1240 | date=January 2014 | doi=10.1093/mnras/stt1932 | doi-access=free | bibcode=2014MNRAS.437.1216D | arxiv=1311.7141 | s2cid=88503488 | postscript=. }}</ref>
<ref name=David2015>{{citation | last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal=The Astrophysical Journal | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | doi=10.1088/0004-637X/804/2/146 | arxiv=1501.03154 | s2cid=33401607 | postscript=. }}</ref>
<ref name=Diaz2011>{{citation | display-authors=1 | last1=Díaz | first1=C. G. | last2=González | first2=J. F. | last3=Levato | first3=H. | last4=Grosso | first4=M. | title=Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum | journal=Astronomy & Astrophysics | volume=531 | page=A143 |date=July 2011 | doi=10.1051/0004-6361/201016386 | bibcode=2011A&A...531A.143D | arxiv=1012.4858 | s2cid=119286673 | postscript=. }}</ref>
<ref name=Mermilliod1986>{{citation | last=Mermilliod | first=J.-C. | title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) | journal=Catalogue of Eggen's UBV Data | publisher=SIMBAD Astronomical Database | date=1986 | bibcode=1986EgUBV........0M | postscript=. }}</ref>
<ref name=SIMBAD>{{cite simbad | title=tau Cen | access-date=2017-01-13 }}</ref> </references>
{{Stars of Centaurus|state=collapsed}}
{{DEFAULTSORT:Tau Centauri}} [[Category:A-type main-sequence stars]] [[Category:Centaurus]] [[Category:Bayer objects|Centauri, Tau]] [[Category:Bright Star Catalogue objects|4802]] [[Category:Durchmusterung objects]] [[Category:Henry Draper Catalogue objects|109787]] [[Category:Hipparcos objects|061622]]