3 Centauri
{{Short description|Triple star system in the constellation Centaurus}}
{{about-distinguish|k Centauri|K Centauri|κ Centauri}}
{{Starbox begin}}
{{Starbox observe
| epoch = J2000.0
| constell = Centaurus
| appmag_v = {{nowrap|4.32 (4.52 + 5.97)}}
}}
{{Starbox character
| class = B5 III-IVp + B8 V
| u-b =
}}
{{Starbox astrometry
}}
{{Starbox astrometry|no_heading=y
| component1 = A
| radial_v =
| prop_mo_ra = {{Val|−34.698|0.864}}
| prop_mo_dec = {{Val|−27.909|0.792}}
| parallax = 11.0982
| p_error = 0.4267
| parallax_footnote =
| absmag_v =
}}
{{Starbox astrometry|no_heading=y
| component1 = B
| radial_v =
| prop_mo_ra = {{Val|−36.737|0.266}}
| prop_mo_dec = {{Val|−23.774|0.189}}
| parallax = 10.2659
| p_error = 0.1380
| absmag_v =
}}
{{Starbox orbit
| primary = Ba
| name = Bb
| period_unitless = 17.428 d
| eccentricity = 0.21
| periastron = 2443296.44 JD
| periarg = 15
| k1 = 17
}}
{{Starbox detail
| component1 = 3 Cen A
| radius =
| luminosity =
| metal_fe =
| rotational_velocity =
| component2 = 3 Cen B
| temperature2 = {{Val|9638|67|66|fmt=commas}}
| luminosity2 = {{Val|50.2|11.7|9.5}}
}}
{{Starbox catalog
| names = {{odlist | B=k Centauri | V=V983 Centauri | F=3 Cen | HIP=67669 | WDS=J13518-3300 }}
| component1 = 3 Cen A
| names1 = {{odlist | HD=120709 | HR=5210 | SAO=204916 | GC=18724 }}
| component2 = 3 Cen B
| names2 = {{odlist | HD=120710 | HR=5211 | SAO=204917 | GC=18725 }}
}}
{{Starbox reference
| Simbad = 3+Cen
| Simbad2 = 3+Cen+A|sn2=A
| Simbad3 = 3+Cen+B|sn3=B
}}
{{Starbox end}}
3 Centauri is a triple star system in the southern constellation of Centaurus, located approximately 300 light years from the Sun. It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.32. As of 2017, the two visible components had an angular separation of {{Val|7.851|ul=arcsecond}} along a position angle of 106°. The system has the Bayer designation k Centauri; 3 Centauri is the Flamsteed designation. It was a suspected eclipsing binary with a variable star designation V983 Centauri, however the AAVSO website lists it as non-variable, formerly suspected to be variable.
The brighter member, designated component A, is a magnitude 4.52 chemically peculiar star of the helium-weak (CP4) variety, and has a stellar classification of B5 III-IVp. The spectrum of the star displays overabundances of elements such as nitrogen, phosphorus, manganese, iron, and nickel, while carbon, oxygen, magnesium, aluminium, sulfur, and chlorine appear underabundant relative to the Sun. Weak emission line features are also visible.
The magnitude 5.97 secondary, component B, is a single-lined spectroscopic binary star system with an orbital period of 17.4 days and an eccentricity of 0.21. The pair have an angular separation of {{Val|2.485|ul=mas}}. The visible component is a B-type main-sequence star with a class of B8 V.
References
{{Reflist|refs=
{{cite simbad | title=3 Cen | access-date=2019-04-11 }}
| title=V0983 Cen | url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=8280
| website=The International Variable Star Index | publisher=American Association of Variable Star Observers
| access-date=22 September 2024}}
| title=Validation of the new Hipparcos reduction
| last1=van Leeuwen | first1=F.
| journal=Astronomy and Astrophysics
| volume=474 | issue=2 | pages=653–664 | year=2007
| arxiv=0708.1752 | bibcode=2007A&A...474..653V
| doi=10.1051/0004-6361:20078357 | s2cid=18759600 }} [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=I/311/hip2&recno=67439 Vizier catalog entry ]
| title=Emission Lines in the Spectrum of the 3HE Star 3 Centauri A
| display-authors=1 | last1=Sigut | first1=T. A. A.
| last2=Landstreet | first2=J. D. | first3=Shorlin | last3=S. L. S.
| journal=The Astrophysical Journal
| volume=530 | issue=2 | pages=L89–L92 | date=February 2000
| doi=10.1086/312499 | pmid=10655172 | bibcode=2000ApJ...530L..89S
| arxiv=astro-ph/0001090 | s2cid=30530913 }}
| title=Spectroscopic abundance analyses of the 3He stars HD 185330 and 3 Cen A
| last1=Sadakane | first1=Kozo | last2=Nishimura | first2=Masayoshi
| journal=Publications of the Astronomical Society of Japan
| volume=70 | issue=3 | id=40 | date=June 2018
| page=40 | doi=10.1093/pasj/psy031 | arxiv=1802.10087
| bibcode=2018PASJ...70...40S }}
| title=Emission lines in the optical spectrum of 3 Cen A
| last1=Wahlgren | first1=G. M. | last2=Hubrig | first2=S.
| journal=Astronomy and Astrophysics
| volume=418 | pages=1073–1081 | date=May 2004
| issue=3 | doi=10.1051/0004-6361:20034257 | bibcode=2004A&A...418.1073W | doi-access=free }}
| 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. | display-authors=1
| 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 | arxiv=astro-ph/0406573 | s2cid=119387088 }}
| last1=Zorec | first1=J. | last2=Royer | first2=F.
| title=Rotational velocities of A-type stars. IV. Evolution of rotational velocities
| journal=Astronomy & Astrophysics
| volume=537 | pages=A120 | year=2012
| bibcode=2012A&A...537A.120Z | arxiv=1201.2052
| doi=10.1051/0004-6361/201117691 | s2cid=55586789 }}
| last1=Pasinetti Fracassini | first1=L. E. | last2=Pastori | first2=L.
| last3=Covino | first3=S. | last4=Pozzi | first4=A.
| title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)
| edition=Third | journal=Astronomy and Astrophysics
| volume=367 | pages=521–524 | date=February 2001
| doi=10.1051/0004-6361:20000451 | bibcode=2001A&A...367..521P
| arxiv=astro-ph/0012289 | s2cid=425754 }}
| 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 }}
| display-authors=1 | last1=Samus | first1=N. N.
| last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V.
| last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N.
| title=General Catalogue of Variable Stars
| version=5.1 | journal=Astronomy Reports
| year=2017 | volume=61 | issue=1 | pages=80–88
| doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=125853869 }}
| title=Spectroscopic study of early-type multiple stellar systems. I. Orbits of spectroscopic binary subsystems
| last1=Veramendi | first1=M. E. | last2=González | first2=J. F.
| journal=Astronomy & Astrophysics
| volume=563 | id=A138 | pages=15 | date=March 2014
| doi=10.1051/0004-6361/201322840 | bibcode=2014A&A...563A.138V | doi-access=free | hdl=11336/4892 | hdl-access=free }}
| last1=Gontcharov | first1=G. A.
| title=Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system
| journal=Astronomy Letters | date=November 2006
| volume=32| issue=11| pages=759–771
| doi=10.1134/S1063773706110065 | bibcode=2006AstL...32..759G
| arxiv=1606.08053 | s2cid=119231169
}}
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| title=XHIP: An extended hipparcos compilation
| journal=Astronomy Letters
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | arxiv=1108.4971
| doi=10.1134/S1063773712050015 | s2cid=119257644 }}
{{cite DR2|6170485544575679104}}
{{cite DR2|6170485544575678592}}
}}
{{Stars of Centaurus}}
{{DEFAULTSORT:3 Centauri}}