# Zeta Centauri

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Star in the constellation Centaurus

Zeta Centauri Location of ζ Centauri (circled) Observation data Epoch J2000.0 Equinox J2000.0 Constellation Centaurus Right ascension 13h 55m 32.38565s[1] Declination −47° 17′ 18.1482″[1] Apparent magnitude (V) +2.55[2] Characteristics Spectral type B2.5 IV[3] U−B color index −0.91[2] B−V color index −0.22[2] Astrometry Radial velocity (Rv) +6.5[4] km/s Proper motion (μ) RA: −57.37[1] mas/yr Dec.: −44.55[1] mas/yr Parallax (π) 8.54±0.13 mas[1] Distance 382 ± 6 ly (117 ± 2 pc) Absolute magnitude (MV) −2.79[5] Orbit[6] Period (P) 8.024 days Semi-major axis (a) 0.0014"[7] Eccentricity (e) 0.5 Periastron epoch (T) 2413719.321 JD Argument of periastron (ω) (secondary) 290° Details Mass 7.8±0.1[3] M☉ Radius 5.80±0.53[8] R☉ Luminosity 5,884[5] L☉ Surface gravity (log g) 3.84±0.08[8] cgs Temperature 23561±283[8] K Rotational velocity (v sin i) 235[9] km/s Age 39.8±5.7[3] Myr Other designations Leepwal, ζ Cen, CD−46 8949, CPD−46 6560, HD 121263, HIP 68002, HR 5231, SAO 224538[10] Database references SIMBAD data

**Zeta Centauri** is a [binary star](/source/Binary_star) system in the southern [constellation](/source/Constellation) of [Centaurus](/source/Centaurus). It has the proper name **Leepwal**;[11] *Zeta Centauri* is its [Bayer designation](/source/Bayer_designation). With a combined [apparent visual magnitude](/source/Apparent_visual_magnitude) of +2.55,[2] it is one of the [brighter members](/source/List_of_stars_in_Centaurus) of the constellation. This system is close enough to the Earth that its distance can be measured directly using the [parallax](/source/Stellar_parallax) technique. This yields a value of roughly 382 [light-years](/source/Light-year) (117 [parsecs](/source/Parsec)), with a 1.6% [margin of error](/source/Margin_of_error).[1] It is drifting further away with a [radial velocity](/source/Radial_velocity) of +6.5 km/s.[4]

ζ Cen is a double-lined [spectroscopic binary](/source/Spectroscopic_binary) system,[12] which indicates that the orbital motion was detected by shifts in the [absorption lines](/source/Absorption_line) of their combined spectra caused by the [Doppler effect](/source/Doppler_effect). The two stars orbit each other over a period of slightly more than eight days with an [orbital eccentricity](/source/Orbital_eccentricity) of about 0.5.[6] The estimated [angular separation](/source/Angular_separation) of the pair is 1.4 [mas](/source/Milliarcsecond).[7]

At an estimated age of 40 million years,[3] the primary component of this system appears to be in the [subgiant](/source/Subgiant_star) stage of its [evolution](/source/Stellar_evolution) with a [stellar classification](/source/Stellar_classification) of B2.5 IV.[3] It is a large star with nearly 8[3] times the mass of the Sun and close to 6[8] times the Sun's radius. This star is rotating rapidly with a [projected rotational velocity](/source/Projected_rotational_velocity) of 235 km s−1.[9]

## Nomenclature

Zeta Centauri, [Latinized](/source/Latinisation_of_names) from ζ Centauri, is the star's [Bayer designation](/source/Bayer_designation). Along with other modern Bayer designations in Centaurus, it was assigned by [Nicolas Louis de Lacaille](/source/Nicolas_Louis_de_Lacaille) in his 1756 star catalog; the star referred to as ζ Centauri in Bayer's *[Uranometria](/source/Uranometria)* of 1603 is [Acrux](/source/Acrux) in the [Southern Cross](/source/Southern_Cross), then considered part of Centaurus.[13]

This star has been referred to by the proper name Alnair [/æˈnɛər/](https://en.wikipedia.org/wiki/Help:IPA/English), from [Arabic](/source/Arabic_language): نير بطن قنطورس, [romanized](/source/Romanization_of_Arabic): *nayyir baṭan qanṭūris*, [lit.](/source/Literal_translation) 'the bright (star) of the body of the [centaur](/source/Centaurus)',[14][15] though this was originally a name for [Acrux](/source/Acrux) (see above).[16][13] Alnair is also the proper name of [α Gruis](/source/Alpha_Gruis) and was officially approved by the IAU as the name of that star.[11] This star has also been referred to as *Baten Kentaurus*, from the same Arabic source.[17]

In [Chinese](/source/Chinese_astronomy), 庫樓 (*Kù Lóu*), meaning *[Arsenal](/source/Horn_(Chinese_constellation))*, refers to an asterism consisting of ζ Centauri, [η Centauri](/source/Eta_Centauri), [θ Centauri](/source/Theta_Centauri), [2 Centauri](/source/2_Centauri), [HD 117440](/source/HD_117440), [ξ1 Centauri](/source/Xi%C2%B9_Centauri), [γ Centauri](/source/Gamma_Centauri), [τ Centauri](/source/Tau_Centauri), [D Centauri](/source/D_Centauri) and [σ Centauri](/source/Sigma_Centauri).[18] Consequently, the [Chinese name](/source/Chinese_star_names) for ζ Centauri itself is 庫樓一 (*Kù Lóu yī*, English: the First Star of Arsenal.)[19] (See also [ι Centauri](/source/Iota_Centauri).)

In [Marshallese](/source/Marshallese_language), this star is named Ļeepwal (pronounced leyepwal), the third of the ten sons of Lōktañūr ([Capella](/source/Capella)).[20] The [IAU Working Group on Star Names](/source/IAU_Working_Group_on_Star_Names) approved the name Leepwal for Zeta Centauri A on 18 July 2024 and it is now so entered in the IAU Catalog of Star Names.[11]

## References

1. ^ [***a***](#cite_ref-aaa474_2_653_1-0) [***b***](#cite_ref-aaa474_2_653_1-1) [***c***](#cite_ref-aaa474_2_653_1-2) [***d***](#cite_ref-aaa474_2_653_1-3) [***e***](#cite_ref-aaa474_2_653_1-4) [***f***](#cite_ref-aaa474_2_653_1-5) van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", *Astronomy and Astrophysics*, **474** (2): 653–664, [arXiv](/source/ArXiv_(identifier)):[0708.1752](https://arxiv.org/abs/0708.1752), [Bibcode](/source/Bibcode_(identifier)):[2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20078357](https://doi.org/10.1051%2F0004-6361%3A20078357), [S2CID](/source/S2CID_(identifier)) [18759600](https://api.semanticscholar.org/CorpusID:18759600)

1. ^ [***a***](#cite_ref-clpl4_99_2-0) [***b***](#cite_ref-clpl4_99_2-1) [***c***](#cite_ref-clpl4_99_2-2) [***d***](#cite_ref-clpl4_99_2-3) Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", *Communications of the Lunar and Planetary Laboratory*, **4** (99): 99, [Bibcode](/source/Bibcode_(identifier)):[1966CoLPL...4...99J](https://ui.adsabs.harvard.edu/abs/1966CoLPL...4...99J)

1. ^ [***a***](#cite_ref-mnras410_1_190_3-0) [***b***](#cite_ref-mnras410_1_190_3-1) [***c***](#cite_ref-mnras410_1_190_3-2) [***d***](#cite_ref-mnras410_1_190_3-3) [***e***](#cite_ref-mnras410_1_190_3-4) [***f***](#cite_ref-mnras410_1_190_3-5) Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", *[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)*, **410** (1): 190–200, [arXiv](/source/ArXiv_(identifier)):[1007.4883](https://arxiv.org/abs/1007.4883), [Bibcode](/source/Bibcode_(identifier)):[2011MNRAS.410..190T](https://ui.adsabs.harvard.edu/abs/2011MNRAS.410..190T), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2010.17434.x](https://doi.org/10.1111%2Fj.1365-2966.2010.17434.x), [S2CID](/source/S2CID_(identifier)) [118629873](https://api.semanticscholar.org/CorpusID:118629873)

1. ^ [***a***](#cite_ref-gcsrv_4-0) [***b***](#cite_ref-gcsrv_4-1) Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", *Carnegie Institute Washington D.C. Publication*, Carnegie Institute of Washington D.C., [Bibcode](/source/Bibcode_(identifier)):[1953GCRV..C......0W](https://ui.adsabs.harvard.edu/abs/1953GCRV..C......0W)

1. ^ [***a***](#cite_ref-Anderson2012_5-0) [***b***](#cite_ref-Anderson2012_5-1) Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", *[Astronomy Letters](/source/Astronomy_Letters)*, **38** (5): 331, [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971), [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A), [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015). [XHIP record for this object](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-ref=VIZ681510a8389ecb&-out.src=V%2F137D%2FXHIP&-nav=cat%3AV%2F137D%26tab%3A{V%2F137D%2FXHIP}%26key%3Asource%3DV%2F137D%2FXHIP%26HTTPPRM%3A&-source=V%2F137D%2FXHIP&-out=HIP&HIP=66657&-out=Comp&-out=Gr&-out=RAJ2000&-out=DEJ2000&-out=Dist&-out=X&-out=Y&-out=Z&-out=SpType&-out=Simbad&-out=Hpmag&-out=Lum&-out=Cst) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-hcoc233_6-0) [***b***](#cite_ref-hcoc233_6-1) Maury, A. C. (1922), "The Orbit of the Spectroscopic Binary ζ Centauri", *Harvard College Observatory Circular*, **233**: 1–4, [Bibcode](/source/Bibcode_(identifier)):[1922HarCi.233....1M](https://ui.adsabs.harvard.edu/abs/1922HarCi.233....1M)

1. ^ [***a***](#cite_ref-aas44_47_7-0) [***b***](#cite_ref-aas44_47_7-1) Halbwachs, J. L. (April 1981), "List of Estimated Angular Separations of Spectroscopic Binaries", *Astronomy and Astrophysics Supplement*, **44**: 47, [Bibcode](/source/Bibcode_(identifier)):[1981A&AS...44...47H](https://ui.adsabs.harvard.edu/abs/1981A&AS...44...47H)

1. ^ [***a***](#cite_ref-aj129_3_1642_8-0) [***b***](#cite_ref-aj129_3_1642_8-1) [***c***](#cite_ref-aj129_3_1642_8-2) [***d***](#cite_ref-aj129_3_1642_8-3) Fitzpatrick, E. L.; Massa, D. (March 2005), "Determining the Physical Properties of the B Stars. II. Calibration of Synthetic Photometry", *The Astronomical Journal*, **129** (3): 1642–1662, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0412542](https://arxiv.org/abs/astro-ph/0412542), [Bibcode](/source/Bibcode_(identifier)):[2005AJ....129.1642F](https://ui.adsabs.harvard.edu/abs/2005AJ....129.1642F), [doi](/source/Doi_(identifier)):[10.1086/427855](https://doi.org/10.1086%2F427855), [S2CID](/source/S2CID_(identifier)) [119512018](https://api.semanticscholar.org/CorpusID:119512018)

1. ^ [***a***](#cite_ref-csrv1970_9-0) [***b***](#cite_ref-csrv1970_9-1) Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", *Contributi Osservatorio Astronomico di Padova in Asiago*, **239** (1): 1, [Bibcode](/source/Bibcode_(identifier)):[1970CoAsi.239....1B](https://ui.adsabs.harvard.edu/abs/1970CoAsi.239....1B)

1. **[^](#cite_ref-SIMBAD_10-0)** ["* zet Cen"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+zet+Cen), *[SIMBAD](/source/SIMBAD)*, [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg), retrieved 2012-03-01.

1. ^ [***a***](#cite_ref-IAU-CSN-new_11-0) [***b***](#cite_ref-IAU-CSN-new_11-1) [***c***](#cite_ref-IAU-CSN-new_11-2) [*IAU Catalog of Star Names*](https://exopla.net/star-names/modern-iau-star-names/), retrieved 22 February 2025.

1. **[^](#cite_ref-aaa446_3_1071_12-0)** van Rensbergen, W.; et al. (February 2006), "Evolution of interacting binaries with a B type primary at birth", *Astronomy and Astrophysics*, **446** (3): 1071–1079, [Bibcode](/source/Bibcode_(identifier)):[2006A&A...446.1071V](https://ui.adsabs.harvard.edu/abs/2006A&A...446.1071V), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20053543](https://doi.org/10.1051%2F0004-6361%3A20053543)

1. ^ [***a***](#cite_ref-Ridpath_13-0) [***b***](#cite_ref-Ridpath_13-1) [Ridpath, Ian](/source/Ian_Ridpath), [*Star Tales - Crux*](http://ianridpath.com/startales/crux.html), retrieved 26 July 2025.

1. **[^](#cite_ref-kunitzsch_smart2006_14-0)** Kunitzsch, P.; Smart, T. (2006), *A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations* (2nd revised ed.), [Cambridge](/source/Cambridge%2C_Massachusetts), [MA](/source/Massachusetts): [Sky Pub](https://en.wikipedia.org/w/index.php?title=New_Track_Media&action=edit&redlink=1), p. 4, [ISBN](/source/ISBN_(identifier)) [978-1-931559-44-7](https://en.wikipedia.org/wiki/Special:BookSources/978-1-931559-44-7)

1. **[^](#cite_ref-15)** *ibid*., p.28.

1. **[^](#cite_ref-allen1899_16-0)** Allen, R.H. (1899), [*Star Names: Their Lore and Meaning*](https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Centaurus*.html), p. 154

1. **[^](#cite_ref-rhoads1971_17-0)** Rhoads, Jack W. (November 15, 1971), [*Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars*](https://ntrs.nasa.gov/api/citations/19720005197/downloads/19720005197.pdf) (PDF), Jet Propulsion Laboratory, California Institute of Technology.

1. **[^](#cite_ref-18)** (in Chinese) *中國星座神話*, written by 陳久金. Published by 台灣書房出版有限公司, 2005, [ISBN](/source/ISBN_(identifier)) [978-986-7332-25-7](https://en.wikipedia.org/wiki/Special:BookSources/978-986-7332-25-7).

1. **[^](#cite_ref-19)** (in Chinese) [AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 25 日](http://aeea.nmns.edu.tw/2006/0607/ap060725.html) [Archived](https://web.archive.org/web/20110522124501/http://aeea.nmns.edu.tw/2006/0607/ap060725.html) 2011-05-22 at the [Wayback Machine](/source/Wayback_Machine)

1. **[^](#cite_ref-ASE_20-0)** ["Leepwal"](https://ase.exopla.net/index.php/Leepwal), *All Skies Encyclopaedia*, [IAU Working Group on Star Names](/source/IAU_Working_Group_on_Star_Names), retrieved 12 May 2025.

v t e Constellation of Centaurus List of stars in Centaurus Centaurus in Chinese astronomy Stars Bayer α A (Rigil Kentaurus) B (Toliman) C (Proxima Centauri) β (Hadar) γ δ ε ζ (Leepwal) η θ (Menkent) ι (Kulou) κ λ μ ν (Heng) ξ1 ξ2 ο1 ο2 π ρ σ τ υ1 υ2 φ χ ψ x1 x2 C3 D E F G H J K M N Q Flamsteed 1 (i) 2 (g) 3 (k) 4 (h) Variable R T V Y RR SV SX BV DY UY V346 V553 V744 V752 V761 (a) V763 (C1) V766 V779 (Krzemiński's star) V803 V810 V816 (Przybylski's Star) V831 V842 V885 V886 V863 V1032 V1369 V1400 V1935 HR 4460 (A) 4466 (C2) 4499 4522 4523 4537 (j) 4546 (B) 4721 4748 (u) 4796 4817 (l) 4831 (w) 4874 (p) 4888 (e) 4889 (n) 4940 (f) 4979 4989 5006 (r) 5041 (m) 5089 (d) 5174 (z) 5222 (y) 5224 5241 5297 5358 (v) 5371 5471 (b) 5485 (c1) 5489 (c2) HD 97413 98176 100453 101581 101930 102117 (Uklun) 103197 107914 108236 109749 110113 113538 113766 114386 114729 115600 116434 (Matza) 117207 117618 (Dofida) 117939 120411 121228 121504 124448 (Popper's Star) 125072 125595 131399 Other 2MASS J1126−5003 2M1207 Gaia BH2 HD 131399 Ab PSR B1259−63 PSR J1311−3430 TOI-763 WASP-15 (Nyamien) WASP-41 WASP-42 WASP-167/KELT-13 Exoplanets 2M1207b b Centauri b HD 101930 b HD 102117 b (Leklsullun) HD 103197 b HD 109749 b HD 113538 b c HD 114386 b HD 114729 b HD 117207 b HD 117618 b (Noifasui) HD 121504 b HIP 65426 b (Najsakopajk) HIP 67522 b NGTS-13b Proxima Centauri b c d WASP-15b (Asye) Star clusters NGC 3766 4230 4507 5281 5286 5316 5460 5617 5662 Other IC 2944 ω Centauri Scorpius–Centaurus association Stock 16 Nebulae NGC 3918 5307 Other Boomerang Nebula Fleming 1 G292.0+1.8 G306.3-0.9 Gum 41 IC 2944 IRAS 13208−6020 RCW 79 RCW 86 Southern Crab Nebula SuWt 2 Galaxies NGC 3557 3568 3749 3783 4444 4603 4622 4650A 4683 4696 4706 4709 4729 4730 4743 4744 4909 4930 4945 4976 5011 A 5026 5064 5082 5090 5091 5102 5114 5121 5128 (Centaurus A) 5161 5206 5253 5266 5291 5398 5408 5419 5483 5516 Other ESO 269-57 ESO 325-4 ESO 383-76 ESO 444-46 Fourcade-Figueroa Object IC 3370 IC 4214 IC 4329A IRAS 13224−3809 J1144−4308 LEDA 677373 PKS 1144−379 PKS 1353−341 PKS 1424−418 Galaxy clusters Abell S740 Centaurus Cluster Shapley Supercluster Astronomical events GW190521 SN 185 SN 1895B (Z) SN 1972E SN 1986G J1407b SN 2019so Category

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Adapted from the Wikipedia article [Zeta Centauri](https://en.wikipedia.org/wiki/Zeta_Centauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Zeta_Centauri?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.