{{Short description|Binary star system in the constellation Centaurus}} {{about-distinguish|y Centauri|Gamma Centauri{{!}}γ (gamma) Centauri|HIP 70969{{!}}Y Centauri}} {{Starbox begin}} {{Starbox observe |epoch=[[J2000]] |constell=[[Centaurus]]<ref name=xhip/> |ra={{RA|13|53|32.76039}}<ref name=HIP>{{cite journal|title=Validation of the new Hipparcos reduction|url=http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL|author=van Leeuwen, F.|display-authors=etal|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}}</ref> |dec={{DEC|-35|39|51.3200}}<ref name=HIP/> |appmag_v=5.565<ref name=SIMBAD>{{cite simbad|title=* y Cen|access-date=19 July 2017}}</ref> {{nowrap|(6.27 / 6.38)‍<ref name=ORB6/>}} }} {{Starbox character |class=F4V (F0V + F1V)<ref name=Cvetkovic>{{cite journal|bibcode=2010SerAJ.180...71C|title=On the Component Masses of Visual Binaries| journal=Serbian Astronomical Journal|volume=180|issue=180|pages=71|author1=Cvetkovic, Z.|last2=Ninkovic, S.|year=2010|doi=10.2298/SAJ1080071C|doi-access=free}}</ref> |b-v=+0.44<ref name=Cousins>{{cite journal|bibcode=1970MNSSA..29....7C|title=Comparison Stars for Long Period Variables and RY Sagittarii|author1=Cousins, A. W. J.|author2=Lagerweij, H. C.|journal=Monthly Notes of the Astron. Soc. Southern Africa|volume=29|issue=7|date=1970}}</ref> |u-b=−0.03<ref name=Cousins/> }} {{Starbox astrometry |radial_v={{val|-8.00|7.40}}<ref name=Kharchenko>{{cite journal|title=Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations|author=Kharchenko, N. V.|display-authors=etal|journal=Astronomische Nachrichten|volume=328|issue=9|page=889|date=2007|bibcode=2007AN....328..889K|doi=10.1002/asna.200710776|arxiv=0705.0878|s2cid=119323941}}</ref> |prop_mo_ra=−83.39<ref name=HIP/> |prop_mo_dec=−25.36<ref name=HIP/> |parallax=19.13 |p_error=0.93 |parallax_footnote=<ref name=HIP/> |absmag_v=+1.84<ref name=xhip>{{cite journal |bibcode=2012AstL...38..331A |title=XHIP: An extended hipparcos compilation |last1=Anderson |first1=E. |last2=Francis |first2=Ch. |journal=Astronomy Letters |date=2012 |volume=38 |issue=5 |page=331 |doi=10.1134/S1063773712050015 |arxiv=1108.4971 }}</ref> }} {{Starbox orbit |reference=<ref name=ORB6>{{cite web|url=http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|title=Sixth Catalog of Orbits of Visual Binary Stars|publisher=United States Naval Observatory|access-date=19 July 2017|archive-date=1 August 2017|archive-url=https://web.archive.org/web/20170801102553/http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|url-status=dead}}</ref> |period=373.0 |axis=1.519 |inclination=74.2 |node=112.3 |periastron=B 1958.57 |eccentricity=0.775 |periarg=90.7 }} {{Starbox detail |component1=HD 120987 A |mass=1.56<ref name=Tokovinin>{{cite journal|bibcode=2014AJ....147...87T|doi=10.1088/0004-6256/147/4/87|arxiv=1401.6827|title=From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs|journal=The Astronomical Journal|volume=147|issue=4|pages=87|year=2014|last1=Tokovinin|first1=Andrei|s2cid=56066740}}</ref> |component2=HD 120987 B |mass2=1.53<ref name=Tokovinin/> }} {{Starbox catalog |names={{odlist|CD=-35°9090|HD=120987|HIP=67819|HR=5222|SAO=204955}}<ref name=SIMBAD/> }} {{Starbox reference |Simbad=HD+120987 }} {{Starbox end}} '''HD 120987''' (''y Centauri'' or ''y Cen'') is a [[star system]] located in the [[constellation]] [[Centaurus]]. HD 120987 is a quintuple [[star system]] located 50 pc (163 [[light years]]) from the [[Sun]]. The system has an apparent magnitude of 5.565.<ref name=SIMBAD/> Based on the system's [[stellar parallax|parallax]], it is located some 172 light-years (52 parsecs) away.<ref name=HIP/>
HD 120987 appears to be a single [[F-type star]] with the [[spectral classification]] F4V, but closer inspection reveals it to be two similar [[F-type main-sequence star]]s with spectral classifications of F0V and F1V, respectively.<ref name=Cvetkovic/> The two orbit each other every 373 years, and are separated by 1.519 arcseconds while taking a very [[orbital eccentricity|eccentric]] orbit.<ref name=ORB6/>
== References == {{reflist}}
{{Stars of Centaurus}}
{{DEFAULTSORT:HD 120987}} [[Category:Centaurus]] [[Category:Bayer objects|Centauri, y]] [[Category:F-type main-sequence stars]] [[Category:Binary stars]] [[Category:Durchmusterung objects]] [[Category:Henry Draper Catalogue objects|120987]] [[Category:Hipparcos objects|067819]] [[Category:Bright Star Catalogue objects|5222]]
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