{{Short description|Star in the constellation Centaurus}} {{about|K Centauri|k Centauri|3 Centauri}} {{Starbox begin}} {{Starbox observe | epoch = J2000.0 | constell = [[Centaurus]]<ref name=Anderson2012/> | ra = {{RA|13|29|25.25471}}<ref name=GaiaDR2/> | dec = {{DEC|−51|09|54.5048}}<ref name=GaiaDR2/> | appmag_v = +5.04<ref name=Anderson2012/> }} {{Starbox character | type = | class = A1V<ref name=houk1978/> | b-v = {{Val|+0.059|0.003}}<ref name=Anderson2012/> | u-b = +0.07 | variable = }} {{Starbox astrometry | radial_v = {{Val|−2.0|4.2}}<ref name=Anderson2012/> | prop_mo_ra = −2.094<ref name=GaiaDR2/> | prop_mo_dec = −5.548<ref name=GaiaDR2/> | parallax = 7.9861 | p_error = 0.2224 | parallax_footnote = <ref name=GaiaDR2/> | absmag_v = −0.91<ref name=Anderson2012/> }} {{Starbox detail | source = | mass = 3.128<ref name=kervella2019/> | radius = 6.635<ref name=mcdonald2017/> | luminosity = 248<ref name=mcdonald2017/> | temperature = 9,167<ref name=mcdonald2017/> | gravity = 2.982<ref name=mcdonald2017/> | metal_fe = | rotational_velocity = {{Val|220.4|2.4}}<ref name=Díaz2011/> | age_gyr = }} {{Starbox catalog | names = {{odlist | B=K Cen | CD=−50°7812 | HD=117150 | HIP=65810 | HR=5071 | SAO=240883 | GC=18220 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = K+Cen }} {{Starbox end}}

'''K Centauri''' is a possible binary [[star]] in the southern [[constellation]] of [[Centaurus]]. It has a white hue and is bright enough to be visible to the naked eye, having an [[apparent visual magnitude]] of +5.04.

K Centauri is located at a distance of approximately 410&nbsp;[[light year]]s from the [[Sun]] based on [[stellar parallax|parallax]], and it has an [[absolute magnitude]] of −0.91.<ref name=Anderson2012/> This is an ordinary [[A-type main-sequence star]] with a [[stellar classification]] of A1V.<ref name=houk1978/> It is spinning rapidly with a [[projected rotational velocity]] of 220&nbsp;km/s,<ref name=Díaz2011/> which is giving it a pronounced [[equatorial bulge]] that is 25% larger than the polar radius.<ref name=vanBelle2012/>

Analysis of [[Hipparcos]] and [[Gaia (spacecraft)|Gaia]] [[astrometry]] suggests that the relatively large margins of error in the calculated parallax may be due to orbital motion caused by an unseen companion. The companion would be an {{jupiter mass|81|link=y}} object orbiting at about {{val|2|ul=AU}}.<ref name=kervella2019/>

== References == {{Reflist|colwidth=30em|refs=

<ref name=GaiaDR2>{{cite DR2|6070059279238254464}}</ref>

<ref name=SIMBAD>{{cite simbad | title=K Cen | access-date=2020-02-12 }}</ref>

<ref name=Anderson2012>{{cite XHIP|65810}}</ref>

<ref name=Díaz2011>{{citation | 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 | display-authors=1 | journal=Astronomy & Astrophysics | volume=531 | page=A143 |date=July 2011 | bibcode=2011A&A...531A.143D | arxiv=1012.4858 | doi=10.1051/0004-6361/201016386 | s2cid=119286673 | postscript=. }}</ref>

<ref name=houk1978>{{citation | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars | volume=2 | location=Ann Arbor | year=1978 | publisher=Dept. of Astronomy, University of Michigan | bibcode=1978mcts.book.....H | postscript=. }}</ref>

<ref name=vanBelle2012>{{citation | last1=van Belle, Gerard T. | title=Interferometric observations of rapidly rotating stars | journal=The Astronomy and Astrophysics Review | volume=20 | issue=1 | page=51 | date=March 2012 | doi=10.1007/s00159-012-0051-2 | bibcode=2012A&ARv..20...51V | postscript=. | arxiv=1204.2572 | s2cid=119273474 }}</ref>

<ref name=kervella2019>{{citation |bibcode=2019A&A...623A..72K |title=Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly |journal=Astronomy and Astrophysics |volume=623 |pages=A72 |last1=Kervella |first1=Pierre |last2=Arenou |first2=Frédéric |last3=Mignard |first3=François |last4=Thévenin |first4=Frédéric |year=2019 |arxiv=1811.08902 |doi=10.1051/0004-6361/201834371 |s2cid=119491061 |postscript=. }}</ref>

<ref name=mcdonald2017>{{citation |bibcode=2017MNRAS.471..770M |title=Fundamental parameters and infrared excesses of Tycho-Gaia stars |journal=Monthly Notices of the Royal Astronomical Society |volume=471 |issue=1 |pages=770 |last1=McDonald |first1=I. |last2=Zijlstra |first2=A. A. |last3=Watson |first3=R. A. |year=2017 |arxiv=1706.02208 |doi=10.1093/mnras/stx1433 |doi-access=free |s2cid=73594365 |postscript=. }}</ref>

}}

{{Stars of Centaurus}}

{{DEFAULTSORT:K Centauri}} [[Category:A-type main-sequence stars]] [[Category:Centaurus]] [[Category:Bayer objects|Centauri, K]] [[Category:Durchmusterung objects]] [[Category:Henry Draper Catalogue objects|117150]] [[Category:Hipparcos objects|065810]] [[Category:Bright Star Catalogue objects|5071]]