{{short description|Binary star system in the constellation Centaurus}} {{DISPLAYTITLE:Upsilon<sup>2</sup> Centauri}} {{other stars by Bayer designation|Upsilon Centauri{{!}}υ Centauri}} {{Starbox begin | name = Upsilon<sup>2</sup> Centauri }} {{Starbox image | image = {{Location mark |image=Centaurus constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=Upsilon2 Centauri |x=400|y=518 }} | caption = Location of υ<sup>2</sup> Centauri (circled in red) }} {{Starbox observe | epoch = [[J2000.0]] | equinox = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Centaurus]] | ra = {{RA|14|01|43.49909 }}<ref name=vanLeeuwen2007/> | dec = {{DEC|−45|36|12.2767}}<ref name=vanLeeuwen2007/> | appmag_v = +4.33<ref name=fernie1983/> }} {{Starbox character | class = F7 II/III<ref name=Houk1978/> | b-v = +0.61<ref name=fernie1983/> | u-b = +0.26<ref name=fernie1983/> | variable = None<ref name=Eggen1985/> }} {{Starbox astrometry | radial_v = {{Val|−7.8|7.4}}<ref name=deBruijne2012/> | prop_mo_ra = {{Val|+8.64|1.09}} | prop_mo_dec = {{Val|-16.25|0.88}} | pm_footnote = <ref name=vanLeeuwen2007/> | parallax = 2.57 | p_error = 1.05 | parallax_footnote = <ref name=vanLeeuwen2007/> | absmag_v = −3.51<ref name=Eggen1985/> }} {{Starbox orbit | reference = <ref name=Pourbaix/> | period_unitless = 207.357 d | eccentricity = 0.55 | periastron = 2423880.5 JD | periarg = 88 | k1 = 12.7 }} {{Starbox detail | source = | mass = {{Val|6.86|0.39}}<ref name=Hohle2010/> | radius = | luminosity_bolometric = 3,919<ref name=Hohle2010/> | temperature = 6,495<ref name=Hohle2010/> | gravity = 2.00<ref name=Mallik2003/> | metal_fe = | rotational_velocity = 0.0<ref name=Mallik2003/> | age_myr = {{Val|45.9|4.0}}<ref name=Tetzlaff2011/> }} {{Starbox catalog | names = {{odlist | B=υ<sup>2</sup> Cen | CD=−44°9040 | HD=122223 | HIP=68523 | HR=5260 | SAO=224621 | GC=18939 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = ups02+Cen }} {{Starbox end}} '''Upsilon<sup>2</sup> Centauri''' is a [[binary star]]<ref name=Pourbaix/> system in the southern [[constellation]] [[Centaurus]]. Its name is a [[Bayer designation]] that is [[Romanization of Greek|Latinized]] from υ<sup>2</sup> Centauri, and abbreviated Upsilon<sup>2</sup> Cen or υ<sup>2</sup> Cen. This system is visible to the [[naked eye]] as a point of light with a combined [[apparent visual magnitude]] of +4.33.<ref name=fernie1983/> Based upon an annual [[stellar parallax|parallax shift]] of {{Val|2.57|ul=mas}} as seen from Earth,<ref name=vanLeeuwen2007/> this star is located roughly 1,300 [[light year]]s from the [[Sun]]. Relative to its neighbors, the system has a [[peculiar velocity]] of {{Val|39.2|8.8|15.2|u=km/s}} and it may form a [[runaway star]] system.<ref name=Tetzlaff2011/>
This is a single-lined [[spectroscopic binary]] star system with an [[orbital period]] of 207.357 days and an [[orbital eccentricity|eccentricity]] of 0.55.<ref name=Pourbaix/> The primary component has the [[stellar spectrum|spectrum]] of an [[stellar evolution|evolved]] [[F-type star|F-type]] [[giant star|giant]]/[[bright giant]] hybrid with a [[stellar classification]] of F7 II/III.<ref name=Houk1978/> It is around 46<ref name=Tetzlaff2011/> million years old with 6.9 times the [[mass of the Sun]]. The star is radiating 3,919 times the [[Sun's luminosity]] from its [[photosphere]] at an [[effective temperature]] of 6,495 K.<ref name=Hohle2010/>
==References== <references> <ref name=vanLeeuwen2007>{{citation | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}</ref>
<ref name=Eggen1985>{{citation | title=Cepheids and nonvariable supergiants | last1=Eggen | first1=O. J. | postscript=. | journal=Astronomical Journal | volume=90 | pages=1260–1277 | date=July 1985 | doi=10.1086/113834 | bibcode=1985AJ.....90.1260E | doi-access=free }}</ref>
<ref name=Mallik2003>{{citation | display-authors=1 | last1=Mallik | first1=Sushma V. | last2=Parthasarathy | first2=M. | last3=Pati | first3=A. K. | title=Lithium and rotation in F and G dwarfs and subgiants | journal=Astronomy and Astrophysics | postscript=. | volume=409 | pages=251–261 | date=October 2003 | doi=10.1051/0004-6361:20031084 | bibcode=2003A&A...409..251M | doi-access=free }}</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=Tetzlaff2011>{{citation | display-authors=1 | last1=Tetzlaff | first1=N. | last2=Neuhäuser | first2=R. | last3=Hohle | first3=M. M. | title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=410 | issue=1 | pages=190–200 | date=January 2011 | doi=10.1111/j.1365-2966.2010.17434.x | doi-access=free | bibcode=2011MNRAS.410..190T | arxiv=1007.4883 | s2cid=118629873 | postscript=. }}</ref>
<ref name=Hohle2010>{{citation | display-authors=1 | last1=Hohle | first1=M. M. | last2=Neuhäuser | first2=R. | last3=Schutz | first3=B. F. | title=Masses and luminosities of O- and B-type stars and red supergiants | journal=Astronomische Nachrichten | volume=331 | issue=4 | page=349 | date=April 2010 | doi=10.1002/asna.200911355 | bibcode=2010AN....331..349H | arxiv=1003.2335 | s2cid=111387483 | postscript=. }}</ref>
<ref name=Pourbaix>{{citation | display-authors=1 | last1=Pourbaix | first1=D. | last2=Tokovinin | first2=A. A. | last3=Batten | first3=A. H. | last4=Fekel | first4=F. C. | last5=Hartkopf | first5=W. I. | last6=Levato | first6=H. | last7=Morrell | first7=N. I. | last8=Torres | first8=G. | last9=Udry | first9=S. | year=2004 | pages=727–732 | volume=424 | title=SB9: The Ninth Catalogue of Spectroscopic Binary Orbits | journal=Astronomy & Astrophysics | bibcode=2004A&A...424..727P | doi=10.1051/0004-6361:20041213 | postscript=. | arxiv=astro-ph/0406573| s2cid=119387088 }}</ref>
<ref name=Houk1978>{{citation | title=Michigan Catalogue of two dimensional spectral types for the HD stars | last=Houk | first=N. | journal=Michigan Spectral Survey | volume=2 | date=1987 | postscript=. | bibcode=1978mcts.book.....H }}</ref>
<ref name=fernie1983>{{citation | title=New UBVRI photometry for 900 supergiants | last=Fernie | first=J. D. | journal=Astrophysical Journal Supplement Series | volume=52 | pages=7 | year=1983 | postscript=. | doi=10.1086/190856 | bibcode=1983ApJS...52....7F | doi-access=free }}</ref>
<ref name=SIMBAD>{{cite simbad | title=ups02 Cen | mode=cs2 | access-date=2017-08-29 }}</ref> </references>
{{Stars of Centaurus|state=collapsed}}
{{DEFAULTSORT:Upsilon2 Centauri}} <!-- Physical properties --> [[Category:F-type bright giants]] [[Category:Spectroscopic binaries]] [[Category:Runaway stars]] <!-- Constellation & catalogues --> [[Category:Centaurus]] [[Category:Bayer objects|Centauri, Upsilon2]] [[Category:Bright Star Catalogue objects|5260]] [[Category:Durchmusterung objects|CD-44 09040]] [[Category:Henry Draper Catalogue objects|122223]] [[Category:Hipparcos objects|068523]]