# Iota Centauri

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Iota_Centauri
> Markdown URL: https://mediated.wiki/source/Iota_Centauri.md
> Source: https://en.wikipedia.org/wiki/Iota_Centauri
> Source revision: 1336846125
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Star in the constellation Centaurus

ι Centauri Location of ι Centauri (circled) Observation data Epoch J2000.0 Equinox J2000.0 Constellation Centaurus[1] Right ascension 13h 20m 35.81737s[2] Declination −36° 42′ 44.2447″[2] Apparent magnitude (V) +2.73[3] Characteristics Evolutionary stage main sequence[4] Spectral type A2 V[1] (kA1.5hA3mA3va)[5] U−B color index +0.01[3] B−V color index +0.03[3] Astrometry Radial velocity (Rv) +0.1[6] km/s Proper motion (μ) RA: −341.11[2] mas/yr Dec.: −86.14[2] mas/yr Parallax (π) 55.49±0.17 mas[2] Distance 58.8 ± 0.2 ly (18.02 ± 0.06 pc) Absolute magnitude (MV) +1.47[1] Details Mass 2.03±0.03[7] M☉ Radius 1.9 ± 0.05[7][a] R☉ Luminosity 22.91+1.08 −1.03[7] L☉ Surface gravity (log g) 4.11[8] cgs Temperature 9,160±70[7] K Metallicity [Fe/H] –0.46[8] dex Rotational velocity (v sin i) 90.3[9] km/s Age 0.35[10] Gyr Other designations Kulou, ι Cen, CD−36°8497, FK5 496, GJ 508.1, GJ 9441, HD 115892, HIP 65109, HR 5028, SAO 204371[11] Database references SIMBAD data

**Iota Centauri** is a [star](/source/Star) in the southern [constellation](/source/Constellation) of [Centaurus](/source/Centaurus). It has the proper name **Kulou**;[12] *Iota Centauri* is its [Bayer designation](/source/Bayer_designation), which is [Latinized](/source/Romanization_of_Greek) from ι Centauri and is abbreviated Iota Cen or ι Cen. Based upon [parallax](/source/Parallax) measurements, it lies at a distance of approximately 58.6 [light-years](/source/Light-year) (18.0 [parsecs](/source/Parsec)) from [Earth](/source/Earth).[2] Iota Centauri has an [apparent visual magnitude](/source/Apparent_visual_magnitude) of +2.73,[3] making it [easily visible](/source/Bortle_Dark-Sky_Scale) to the naked eye.

The spectrum of ι Centauri matches a [stellar classification](/source/Stellar_classification) of A2 V. It is an [A-type main sequence star](/source/A-type_main_sequence_star) that is generating energy by the [nuclear fusion](/source/Nuclear_fusion) of hydrogen in its core region. This energy is being radiated from the outer envelope of the star at an [effective temperature](/source/Effective_temperature) of 9,160 K,[7] giving the star a white hue.[13] It has about 2 times the [Sun's mass](/source/Solar_mass), 1.9 times the [Sun's radius](/source/Solar_radius),[7] and is roughly 350 million years old.[10] The abundance of elements other than hydrogen and helium, what astronomers term the [metallicity](/source/Metallicity), is only 35% of the abundance in the Sun.[8] A weak [magnetic field](/source/Stellar_magnetic_field) has been tentatively identified with a strength of −77 ± 30 [G](/source/Gauss_(unit)).[14]

This star has an [excess emission of infrared](/source/Infrared_excess) indicating it is surrounded by a circumstellar disk of dust, known as a [debris disk](/source/Debris_disk). The disk is located within an orbital radius of six [Astronomical Units](/source/Astronomical_Unit) from the star. The dust is unusually luminous for a star this age, suggesting that some process may have recently increased the amount of debris, such as collisions between [planetesimals](/source/Planetesimal). Alternatively, the planetesimals in this system may have unusual physical properties. As of 2011, a search for planets in this system has thus far been unsuccessful.[10]

Iota Centauri appears to belong to the [stellar kinematic group](/source/Stellar_kinematic_group) known as IC 2391. This is a group of around 16 co-moving stars that most likely originated in the same [molecular cloud](/source/Molecular_cloud) at least 45 million years ago.[15]

## Nomenclature

In [Chinese](/source/Chinese_astronomy), 柱 (*Zhǔ*), meaning *[Pillars](/source/Horn_(Chinese_constellation))*, refers to an asterism consisting of ι Centauri, [υ2 Centauri](/source/Upsilon2_Centauri), [υ1 Centauri](/source/Upsilon1_Centauri), [a Centauri](/source/V761_Centauri), [ψ Centauri](/source/Psi_Centauri), [4 Centauri](/source/4_Centauri), [3 Centauri](/source/3_Centauri) and [1 Centauri](/source/1_Centauri).[16] Consequently, the [Chinese name](/source/Chinese_star_names) for ι Centauri itself is 柱十一 (*Zhǔ shíyī*, English: the Eleventh Star of Pillars.)[17]

In older Chinese sources,[18] this star was a member of the ancient super-constellation Kulou (库楼, The Arsenal), in the area of modern [Centaurus](/source/Centaurus) and [Lupus](/source/Lupus_(constellation)), dating back to the 2nd century BCE.[12] Later, [ζ Centauri](/source/Zeta_Centauri) was identified as the main star of Kulou.[18] The [IAU Working Group on Star Names](/source/IAU_Working_Group_on_Star_Names) approved the name Kulou for this star on 17 February 2025 and it is now so entered in the IAU Catalog of Star Names.[12]

## Notes

1. **[^](#cite_ref-rad_8-0)** Calculated, using the [Stefan-Boltzmann law](/source/Stefan-Boltzmann_law) and the star's [effective temperature](/source/Effective_temperature) and luminosity, with respect to the [solar](/source/Sun) nominal effective temperature of 5,772 [K](/source/Kelvin): ( 5 , 772 9 , 160 ) 4 ⋅ 10 1.36 = 1.9 R ⊙ . {\displaystyle {\sqrt {{\biggl (}{\frac {5,772}{9,160}}{\biggr )}^{4}\cdot 10^{1.36}}}=1.9\ R_{\odot }.}

## References

1. ^ [***a***](#cite_ref-Anderson2012_1-0) [***b***](#cite_ref-Anderson2012_1-1) [***c***](#cite_ref-Anderson2012_1-2) 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=65109&-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-aaa474_2_653_2-0) [***b***](#cite_ref-aaa474_2_653_2-1) [***c***](#cite_ref-aaa474_2_653_2-2) [***d***](#cite_ref-aaa474_2_653_2-3) [***e***](#cite_ref-aaa474_2_653_2-4) [***f***](#cite_ref-aaa474_2_653_2-5) 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_3-0) [***b***](#cite_ref-clpl4_99_3-1) [***c***](#cite_ref-clpl4_99_3-2) [***d***](#cite_ref-clpl4_99_3-3) 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. **[^](#cite_ref-hu2023_4-0)** Hardegree-Ullman, Kevin K.; et al. (2023), "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets", *The Astronomical Journal*, **165** (6): 267, [arXiv](/source/ArXiv_(identifier)):[2304.12490](https://arxiv.org/abs/2304.12490), [Bibcode](/source/Bibcode_(identifier)):[2023AJ....165..267H](https://ui.adsabs.harvard.edu/abs/2023AJ....165..267H), [doi](/source/Doi_(identifier)):[10.3847/1538-3881/acd1ec](https://doi.org/10.3847%2F1538-3881%2Facd1ec).

1. **[^](#cite_ref-aj132_1_161_5-0)** Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", *[The Astronomical Journal](/source/The_Astronomical_Journal)*, **132** (1): 161–170, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0603770](https://arxiv.org/abs/astro-ph/0603770), [Bibcode](/source/Bibcode_(identifier)):[2006AJ....132..161G](https://ui.adsabs.harvard.edu/abs/2006AJ....132..161G), [doi](/source/Doi_(identifier)):[10.1086/504637](https://doi.org/10.1086%2F504637), [S2CID](/source/S2CID_(identifier)) [119476992](https://api.semanticscholar.org/CorpusID:119476992).

1. **[^](#cite_ref-scfs_6-0)** Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", *Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg*, **35** (35), Astronomisches Rechen-Institut Heidelberg: 1, [Bibcode](/source/Bibcode_(identifier)):[1999VeARI..35....1W](https://ui.adsabs.harvard.edu/abs/1999VeARI..35....1W).

1. ^ [***a***](#cite_ref-pearce_7-0) [***b***](#cite_ref-pearce_7-1) [***c***](#cite_ref-pearce_7-2) [***d***](#cite_ref-pearce_7-3) [***e***](#cite_ref-pearce_7-4) [***f***](#cite_ref-pearce_7-5) Pearce, Tim D.; et al. (2022-03-01), "Planet populations inferred from debris discs. Insights from 178 debris systems in the ISPY, LEECH, and LIStEN planet-hunting surveys", *Astronomy and Astrophysics*, **659**: A135, [arXiv](/source/ArXiv_(identifier)):[2201.08369](https://arxiv.org/abs/2201.08369), [Bibcode](/source/Bibcode_(identifier)):[2022A&A...659A.135P](https://ui.adsabs.harvard.edu/abs/2022A&A...659A.135P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202142720](https://doi.org/10.1051%2F0004-6361%2F202142720), [ISSN](/source/ISSN_(identifier)) [0004-6361](https://search.worldcat.org/issn/0004-6361).

1. ^ [***a***](#cite_ref-aaa490_1_297_9-0) [***b***](#cite_ref-aaa490_1_297_9-1) [***c***](#cite_ref-aaa490_1_297_9-2) Saffe, C.; et al. (October 2008), "Spectroscopic metallicities of Vega-like stars", *Astronomy and Astrophysics*, **490** (1): 297–305, [arXiv](/source/ArXiv_(identifier)):[0805.3936](https://arxiv.org/abs/0805.3936), [Bibcode](/source/Bibcode_(identifier)):[2008A&A...490..297S](https://ui.adsabs.harvard.edu/abs/2008A&A...490..297S), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:200810260](https://doi.org/10.1051%2F0004-6361%3A200810260), [S2CID](/source/S2CID_(identifier)) [15059920](https://api.semanticscholar.org/CorpusID:15059920).

1. **[^](#cite_ref-aaa531_A143_10-0)** Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", *Astronomy & Astrophysics*, **531**: A143, [arXiv](/source/ArXiv_(identifier)):[1012.4858](https://arxiv.org/abs/1012.4858), [Bibcode](/source/Bibcode_(identifier)):[2011A&A...531A.143D](https://ui.adsabs.harvard.edu/abs/2011A&A...531A.143D), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201016386](https://doi.org/10.1051%2F0004-6361%2F201016386), [S2CID](/source/S2CID_(identifier)) [119286673](https://api.semanticscholar.org/CorpusID:119286673).

1. ^ [***a***](#cite_ref-apjl736_2_L32_11-0) [***b***](#cite_ref-apjl736_2_L32_11-1) [***c***](#cite_ref-apjl736_2_L32_11-2) Quanz, Sascha P.; et al. (August 2011), "Searching for Gas Giant Planets on Solar System Scales: VLT NACO/APP Observations of the Debris Disk Host Stars HD172555 and HD115892", *The Astrophysical Journal Letters*, **736** (2): L32, [arXiv](/source/ArXiv_(identifier)):[1106.4528](https://arxiv.org/abs/1106.4528), [Bibcode](/source/Bibcode_(identifier)):[2011ApJ...736L..32Q](https://ui.adsabs.harvard.edu/abs/2011ApJ...736L..32Q), [doi](/source/Doi_(identifier)):[10.1088/2041-8205/736/2/L32](https://doi.org/10.1088%2F2041-8205%2F736%2F2%2FL32), [S2CID](/source/S2CID_(identifier)) [118506333](https://api.semanticscholar.org/CorpusID:118506333).

1. **[^](#cite_ref-SIMBAD_12-0)** ["iot Cen"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=iot+Cen), *[SIMBAD](/source/SIMBAD)*, [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg), retrieved 2012-02-02.

1. ^ [***a***](#cite_ref-IAU-CSN-new_13-0) [***b***](#cite_ref-IAU-CSN-new_13-1) [***c***](#cite_ref-IAU-CSN-new_13-2) [*IAU Catalog of Star Names*](https://exopla.net/star-names/modern-iau-star-names/), retrieved 22 February 2025.

1. **[^](#cite_ref-csiro_14-0)** ["The Colour of Stars"](https://web.archive.org/web/20120318151427/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html), *Australia Telescope, Outreach and Education*, [Commonwealth Scientific and Industrial Research Organisation](/source/Commonwealth_Scientific_and_Industrial_Research_Organisation), December 21, 2004, archived from [the original](http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html) on March 18, 2012, retrieved 2012-01-16.

1. **[^](#cite_ref-aaa446_3_1089_15-0)** Hubrig, S.; et al. (February 2006), "Accurate magnetic field measurements of Vega-like stars and Herbig Ae/Be stars", *Astronomy and Astrophysics*, **446** (3): 1089–1094, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0510157](https://arxiv.org/abs/astro-ph/0510157), [Bibcode](/source/Bibcode_(identifier)):[2006A&A...446.1089H](https://ui.adsabs.harvard.edu/abs/2006A&A...446.1089H), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20053794](https://doi.org/10.1051%2F0004-6361%3A20053794), [S2CID](/source/S2CID_(identifier)) [14669402](https://api.semanticscholar.org/CorpusID:14669402).

1. **[^](#cite_ref-aj140_3_713_16-0)** Nakajima, Tadashi; et al. (September 2010), "Potential Members of Stellar Kinematical Groups within 20 pc of the Sun", *The Astronomical Journal*, **140** (3): 713–722, [Bibcode](/source/Bibcode_(identifier)):[2010AJ....140..713N](https://ui.adsabs.harvard.edu/abs/2010AJ....140..713N), [doi](/source/Doi_(identifier)):[10.1088/0004-6256/140/3/713](https://doi.org/10.1088%2F0004-6256%2F140%2F3%2F713).

1. **[^](#cite_ref-17)** (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-18)** (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. ^ [***a***](#cite_ref-ASE_19-0) [***b***](#cite_ref-ASE_19-1) ["Kulou (库楼)"](https://ase.exopla.net/index.php/Kulou), *All Skies Encyclopaedia*, [IAU Working Group on Star Names](/source/IAU_Working_Group_on_Star_Names), retrieved 6 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

---
Adapted from the Wikipedia article [Iota Centauri](https://en.wikipedia.org/wiki/Iota_Centauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Iota_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.