4 Centauri

{{Short description|Star in the constellation Centaurus}} {{about-distinguish|h Centauri|V945 Centauri{{!}}H Centauri}} {{Starbox begin}} {{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=4 Centauri |x=415|y=215 }} | caption = Location of 4 Centauri (circled in red) }} {{Starbox observe 2s | epoch = J2000.0 | constell = [[Centaurus]]<ref name=xhip/> | component1 = A | ra1 = {{RA|13|53|12.53829}}<ref name=dr3a/> | dec1 = {{DEC|−31|55|39.4304}}<ref name=dr3a/> | appmag_v1 = +4.72<ref name=usno>{{cite journal|bibcode=2001AJ....122.3466M|title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog|journal=The Astronomical Journal|volume=122|issue=6|pages=3466|last1=Mason|first1=Brian D.|last2=Wycoff|first2=Gary L.|last3=Hartkopf|first3=William I.|last4=Douglass|first4=Geoffrey G.|last5=Worley|first5=Charles E.|year=2001|doi=10.1086/323920|doi-access=free}}</ref> | component2 = B | ra2 = {{RA|13|53|12.43506}}<ref name=dr3b/> | dec2 = {{DEC|−31|55|54.1506}}<ref name=dr3b/> | appmag_v2 = +8.47<ref name=nicolet>{{cite journal|bibcode=1978A&AS...34....1N|title=Catalogue of homogeneous data in the UBV photoelectric photometric system|journal=Astronomy and Astrophysics|volume=34|pages=1|last1=Nicolet|first1=B.|year=1978}}</ref>) }} {{Starbox character | component1 = A | type = [[main sequence]]<ref name=dr3a/> | class = B6IV<ref name=Levato/> | b-v = −0.14<ref name=UBV>{{cite journal |last1=Mallama |first1=A. |title=Sloan Magnitudes for the Brightest Stars |journal=Journal of the American Association of Variable Star Observers (Jaavso) |date=2014 |volume=42 |issue=2 |page=443 |bibcode=2014JAVSO..42..443M }}</ref> | u-b = −0.56<ref name=UBV/> | variable = | component2 = B | type2 = [[main sequence]]<ref name=dr3b/> | class2 = Am<ref name=Levato/> | b-v2 = +0.30<ref name=renson2009>{{cite journal |last1=Renson |first1=P. |last2=Manfroid |first2=J. |title=Catalogue of Ap, HGMN and Am stars |journal=Astronomy and Astrophysics |date=2009 |volume=498 |issue=3 |page=961 |doi=10.1051/0004-6361/200810788 |bibcode=2009A&A...498..961R }}</ref> | u-b2 = +0.10<ref name=renson2009/> | variabl2e = }} {{Starbox astrometry | component1 = A | radial_v = {{val|+5.2|2}}<ref name=GCRV>{{cite journal |last1=Evans |first1=D. S. |title=The Revision of the General Catalogue of Radial Velocities |journal=Determination of Radial Velocities and Their Applications |date=1967 |volume=30 |page=57 |bibcode=1967IAUS...30...57E }}</ref> | prop_mo_ra = −10.428<ref name=dr3a/> | prop_mo_dec = −10.710<ref name=dr3a/> | parallax = 4.8225 | p_error = 0.1539 | parallax_footnote = <ref name=dr3a>{{cite Gaia DR3|6171681877649374080}}</ref> | absmag_v = −1.66<ref name=xhip/> | component2 = B | radial_v2 = {{val|+9|10}}<ref name=GCRV/> | prop_mo_ra2 = −10.905<ref name=dr3b/> | prop_mo_dec2 = −10.625<ref name=dr3b/> | parallax2 = 4.1269 | p_error2 = 0.1312 | parallax_footnote2 = <ref name=dr3b>{{cite Gaia DR3|6171681881946274304}}</ref> | absmag_v2 = }} {{Starbox orbit |reference=<ref name=Levato/> |primary=4 Cen Aa |name=4 Cen Ab |period_unitless={{val|6.930137|0.000015|u=days}} |periastron={{val|fmt=none||2418823.406|0.10}} |k1={{val|21.0|1.5}} |eccentricity={{val|0.25|0.10}} |periarg={{val|152|17}} }} {{Starbox orbit |reference=<ref name=Levato/> |primary=4 Cen Ba |name=4 Cen Bb |period_unitless={{val|4.8390|0.0001|u=days}} |periastron={{val|fmt=none|2442916.55|0.09}} |k1={{val|16.9|3.5}} |eccentricity={{val|0.05|0.02}} |periarg={{val|51|20}} }} {{Starbox detail | component1 = Aa | mass = 7.7<ref name=msc>{{cite journal |last1=Tokovinin |first1=Andrei |title=The Updated Multiple Star Catalog |journal=The Astrophysical Journal Supplement Series |date=2018 |volume=235 |issue=1 |page=6 |doi=10.3847/1538-4365/aaa1a5 |doi-access=free |arxiv=1712.04750 |bibcode=2018ApJS..235....6T }}</ref> | temperature = 14,322<ref name=quintana2025>{{cite journal |last1=Quintana |first1=Alexis L. |last2=Wright |first2=Nicholas J. |last3=Martínez García |first3=Juan |title=A census of OB stars within 1 KPC and the star formation and core collapse supernova rates of the Milky Way |journal=Monthly Notices of the Royal Astronomical Society |date=2025 |volume=538 |issue=3 |page=1367 |doi=10.1093/mnras/staf083 |doi-access=free |arxiv=2503.08286 |bibcode=2025MNRAS.538.1367Q }}</ref> | luminosity = 687<ref name=quintana2025/> | radius = 6.2<ref name=dr3a/> | gravity = 3.43<ref name=dr3a/> | metal_fe = −1.06<ref name=dr3a/> | rotation = 27.2 days<ref name=oelkers2018>{{cite journal |last1=Oelkers |first1=Ryan J. |last2=Rodriguez |first2=Joseph E. |last3=Stassun |first3=Keivan G. |last4=Pepper |first4=Joshua |last5=Somers |first5=Garrett |last6=Kafka |first6=Stella |last7=Stevens |first7=Daniel J. |last8=Beatty |first8=Thomas G. |last9=Siverd |first9=Robert J. |last10=Lund |first10=Michael B. |last11=Kuhn |first11=Rudolf B. |last12=James |first12=David |last13=Gaudi |first13=B. Scott |title=Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey |journal=The Astronomical Journal |date=2018 |volume=155 |issue=1 |page=39 |doi=10.3847/1538-3881/aa9bf4 |doi-access=free |arxiv=1711.03608 |bibcode=2018AJ....155...39O }}</ref> | age_myr = 51<ref name=tetzlaff2011>{{cite journal |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 |date=2011 |volume=410 |issue=1 |page=190 |doi=10.1111/j.1365-2966.2010.17434.x |doi-access=free |arxiv=1007.4883 |bibcode=2011MNRAS.410..190T }}</ref> | component2 = Ab | mass2 = 0.75<ref name=msc/> }} {{Starbox detail | component1 = Ba | mass = 1.9<ref name=msc/> | temperature = 7,440<ref name=tic>{{cite journal |last1=Stassun |first1=Keivan G. |last2=Oelkers |first2=Ryan J. |last3=Paegert |first3=Martin |last4=Torres |first4=Guillermo |last5=Pepper |first5=Joshua |last6=De Lee |first6=Nathan |last7=Collins |first7=Kevin |last8=Latham |first8=David W. |last9=Muirhead |first9=Philip S. |last10=Chittidi |first10=Jay |last11=Rojas-Ayala |first11=Bárbara |last12=Fleming |first12=Scott W. |last13=Rose |first13=Mark E. |last14=Tenenbaum |first14=Peter |last15=Ting |first15=Eric B. |last16=Kane |first16=Stephen R. |last17=Barclay |first17=Thomas |last18=Bean |first18=Jacob L. |last19=Brassuer |first19=C. E. |last20=Charbonneau |first20=David |last21=Ge |first21=Jian |last22=Lissauer |first22=Jack J. |last23=Mann |first23=Andrew W. |last24=McLean |first24=Brian |last25=Mullally |first25=Susan |last26=Narita |first26=Norio |last27=Plavchan |first27=Peter |last28=Ricker |first28=George R. |last29=Sasselov |first29=Dimitar |last30=Seager |first30=S. |display-authors=1 |title=The Revised TESS Input Catalog and Candidate Target List |journal=The Astronomical Journal |date=2019 |volume=158 |issue=4 |page=138 |doi=10.3847/1538-3881/ab3467 |doi-access=free |arxiv=1905.10694 |bibcode=2019AJ....158..138S }}</ref> | luminosity = 17.0<ref name=tic/> | radius = 2.48<ref name=tic/> | gravity = 3.88<ref name=tic/> | component2 = Bb | mass2 = 0.22<ref name=msc/> }} {{Starbox catalog |names={{odlist |B=h Cen |F=4 Cen |HD=120955 |HR=5221 |CCDM=J13532-3156 }}<ref>{{cite simbad|title=* 4 Cen|access-date=8 February 2018}}</ref> |component1=A |names1={{odlist |SAO=204944 |GC=18755 |CD=−31°10729 |HIP=67786 }}<ref>{{cite simbad|title=* 4 Cen A|access-date=8 February 2018}}</ref> |component2=B |names2={{odlist |SAO=204943 |GC=18754 |CD=−31°10727 }}<ref>{{cite simbad|title=* 4 Cen B|access-date=8 February 2018}}</ref> }} {{Starbox reference | Simbad=HD+120955 | Simbad3=*+4+Cen+B|sn3=4 Cen B }} {{Starbox end}} '''4 Centauri''' is a [[multiple star]] in the [[constellation]] [[Centaurus]], approximately 640 [[light year]]s from [[Earth]]. It has a combined [[apparent magnitude]] of +4.71.<ref>{{cite journal |last1=Paunzen |first1=E. |title=Catalogue of stars measured in the Geneva seven-colour photometric system |journal=Astronomy and Astrophysics |date=2022 |volume=661 |pages=A89 |doi=10.1051/0004-6361/202142355 |arxiv=2111.04810 |bibcode=2022A&A...661A..89P }}</ref> The primary is a blue-white [[stellar classification|B-type]] [[subgiant]] with a spectroscopic companion, while the secondary is an [[Am star]] also with a spectroscopic companion.

4 Centauri is a hierarchical quadruple [[star system]]. The primary component of the system, 4 Centauri A, is a [[spectroscopic binary]], meaning that its components cannot be [[angular resolution|resolved]] but periodic [[Doppler shift]]s in its [[stellar spectrum|spectrum]] show that it must be orbiting. 4 Centauri A has an [[orbital period]] of 6.927 days and an [[orbital eccentricity|eccentricity]] of 0.23. Because light from only one of the stars can be detected (i.e. it is a single-lined spectroscopic binary), some parameters such as its inclination are unknown.<ref>{{cite journal|title=The Spectroscopic Binary H 4 Centauri|author=Paddock, G. F.|journal=Publications of the Astronomical Society of the Pacific|volume=29|number=167|page=56|date=1917|bibcode=1917PASP...29...56P|doi=10.1086/122588|s2cid=120812946 |url=https://zenodo.org/record/1431275}}</ref> The secondary component, is also a single-lined spectroscopic binary. It has an orbital period of 4.839 days and an eccentricity of 0.05. The secondary component is a metallic-lined [[A-type star]]. The two pairs themselves are separated by 14 arcseconds; one orbit would take at least 55,000 years.<ref name=Levato>{{cite journal|title=Stellar multiplicity in the Scorpius-Centaurus association|author1=Levato, H.|author2=Malaroda, S.|author3=Morrell, N.|author4=Solivella, G.|journal=Astrophysical Journal Supplement Series|volume=64|pages=487–503|date=1987|bibcode=1987ApJS...64..487L|doi=10.1086/191204}}</ref>

==References== {{Reflist|refs=

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[[Category:Centaurus]] [[Category:B-type subgiants]] [[Category:Bayer objects|Centauri, h]] [[Category:Flamsteed objects|Centauri, 4]] [[Category:Spectroscopic binaries]] [[Category:Multiple star systems|4]] [[Category:Bright Star Catalogue objects|5221]] [[Category:Henry Draper Catalogue objects|120955]] [[Category:Hipparcos objects|067786]] [[Category:Durchmusterung objects|CD-31 10729]] [[Category:Am stars]] [[Category:A-type main-sequence stars]]