# Y Centauri

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Variable star in the constellation Centaurus

Not to be confused with [y Centauri](/source/HD_120987), [γ Centauri](/source/Gamma_Centauri), or [υ Centauri](/source/Upsilon_Centauri).

Y Centauri A visual band light curve for Y Centauri, plotted from ASAS data[1] Observation data Epoch J2000.0 Equinox J2000.0 Constellation Centaurus Right ascension 14h 30m 58.61656s[2] Declination −30° 05′ 51.8706″[2] Apparent magnitude (V) 8.0 - 9.1[3] Characteristics Evolutionary stage AGB[4] Spectral type M4e - M7[3] U−B color index +0.72[5] B−V color index +1.44[5] Variable type SRb[3] Astrometry Radial velocity (Rv) −6.00[6] km/s Proper motion (μ) RA: −38.874[7] mas/yr Dec.: −25.867[7] mas/yr Parallax (π) 4.4510±0.2738 mas[7] Distance 730 ± 50 ly (220 ± 10 pc) Details Radius 48[7] R☉ Luminosity 330[7] L☉ Surface gravity (log g) −0.315[8] cgs Temperature 3,557[7] K Other designations Y Cen, HD 127233, BD−29°11116, HIP 70969, SAO 182618, GC 19563, IRAS 14280-2952, AAVSO 1425-29 Database references SIMBAD data

**Y Centauri** or **Y Cen** (*HD 127233*, *HIP 70969*) is a [semiregular variable star](/source/Semiregular_variable_star) in the constellation of [Centaurus](/source/Centaurus).

The variability in the star was discovered by [Williamina Fleming](/source/Williamina_Fleming) in 1895 and published in the *Third Catalogue of Variable Stars*. The photographic magnitude range was given as 7.7 - 8.8, but the variability was described as "somewhat doubtful".[9] It was later given the designation HV 52 in the Harvard Catalogue of Variable Stars.[10] The [General Catalogue of Variable Stars](/source/General_Catalogue_of_Variable_Stars) lists it as a semiregular variable star with a period of 180 days and a visual magnitude range of 8.0 - 9.1.[3] A study of [Hipparcos satellite](/source/Hipparcos_satellite) photometry found a small amplitude range of 0.2 magnitudes at a visual magnitude of 8.53.[11]

The distance of the star is poorly known. The revised Hipparcos annual parallax of 3.50 mas gives a distance of 900 light years.[2] A study taking into account the variability of the star found a parallax of 5.57 mas, corresponding to a distance of 585 light years.[12] Both estimates have a margin of error over 20%. The [Gaia Data Release 2](/source/Gaia_Data_Release_2) parallax lies between these two values and appears more accurate with a margin of error around 5%, but with a large value for astrometric noise.[7] [Gaia EDR3](/source/Gaia_EDR3) does not list a parallax for this star.[13]

Y Centauri is an [asymptotic giant branch](/source/Asymptotic_giant_branch) star[4] 330 times as luminous as the sun. Its spectral type varies between M4 and M7 as it pulsates.[3]

The star has been observed to produce 22 GHz water [maser](/source/Maser) emission,[14] although later searches did not find any maser emission.[4]

## References

1. **[^](#cite_ref-ASASServer_1-0)** ["ASAS All Star Catalogue"](http://www.astrouw.edu.pl/asas/?page=aasc). The All Sky Automated Survey. Retrieved 8 December 2021.

1. ^ [***a***](#cite_ref-hipparcos_2-0) [***b***](#cite_ref-hipparcos_2-1) [***c***](#cite_ref-hipparcos_2-2) Van Leeuwen, F. (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-gcvs_3-0) [***b***](#cite_ref-gcvs_3-1) [***c***](#cite_ref-gcvs_3-2) [***d***](#cite_ref-gcvs_3-3) [***e***](#cite_ref-gcvs_3-4) Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". *VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S*. **1**: 02025. [Bibcode](/source/Bibcode_(identifier)):[2009yCat....102025S](https://ui.adsabs.harvard.edu/abs/2009yCat....102025S).

1. ^ [***a***](#cite_ref-yoon_4-0) [***b***](#cite_ref-yoon_4-1) [***c***](#cite_ref-yoon_4-2) Yoon, Dong-Hwan; Cho, Se-Hyung; Kim, Jaeheon; Yun, Young joo; Park, Yong-Sun (2014). ["SiO and H2O Maser Survey toward Post-asymptotic Giant Branch and Asymptotic Giant Branch Stars"](https://doi.org/10.1088%2F0067-0049%2F211%2F1%2F15). *The Astrophysical Journal Supplement*. **211** (1): 15. [Bibcode](/source/Bibcode_(identifier)):[2014ApJS..211...15Y](https://ui.adsabs.harvard.edu/abs/2014ApJS..211...15Y). [doi](/source/Doi_(identifier)):[10.1088/0067-0049/211/1/15](https://doi.org/10.1088%2F0067-0049%2F211%2F1%2F15). [S2CID](/source/S2CID_(identifier)) [73561291](https://api.semanticscholar.org/CorpusID:73561291).

1. ^ [***a***](#cite_ref-ducati_5-0) [***b***](#cite_ref-ducati_5-1) Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". *CDS/ADC Collection of Electronic Catalogues*. **2237**: 0. [Bibcode](/source/Bibcode_(identifier)):[2002yCat.2237....0D](https://ui.adsabs.harvard.edu/abs/2002yCat.2237....0D).

1. **[^](#cite_ref-pulkovo_6-0)** Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". *Astronomy Letters*. **32** (11): 759–771. [arXiv](/source/ArXiv_(identifier)):[1606.08053](https://arxiv.org/abs/1606.08053). [Bibcode](/source/Bibcode_(identifier)):[2006AstL...32..759G](https://ui.adsabs.harvard.edu/abs/2006AstL...32..759G). [doi](/source/Doi_(identifier)):[10.1134/S1063773706110065](https://doi.org/10.1134%2FS1063773706110065). [S2CID](/source/S2CID_(identifier)) [119231169](https://api.semanticscholar.org/CorpusID:119231169).

1. ^ [***a***](#cite_ref-dr2_7-0) [***b***](#cite_ref-dr2_7-1) [***c***](#cite_ref-dr2_7-2) [***d***](#cite_ref-dr2_7-3) [***e***](#cite_ref-dr2_7-4) [***f***](#cite_ref-dr2_7-5) [***g***](#cite_ref-dr2_7-6) [Brown, A. G. A.](/source/Anthony_Brown_(scientist)); et al. ([Gaia collaboration](/source/Data_Processing_and_Analysis_Consortium)) (August 2018). ["*Gaia* Data Release 2: Summary of the contents and survey properties"](https://doi.org/10.1051%2F0004-6361%2F201833051). *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **616**. A1. [arXiv](/source/ArXiv_(identifier)):[1804.09365](https://arxiv.org/abs/1804.09365). [Bibcode](/source/Bibcode_(identifier)):[2018A&A...616A...1G](https://ui.adsabs.harvard.edu/abs/2018A&A...616A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201833051](https://doi.org/10.1051%2F0004-6361%2F201833051). [Gaia DR2 record for this source](https://vizier.u-strasbg.fr/viz-bin/VizieR-S?Gaia%20DR2%206220360697682027392) at [VizieR](/source/VizieR).

1. **[^](#cite_ref-mcdonald2017_8-0)** McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). ["Fundamental parameters and infrared excesses of Tycho-Gaia stars"](https://doi.org/10.1093%2Fmnras%2Fstx1433). *Monthly Notices of the Royal Astronomical Society*. **471** (1): 770. [arXiv](/source/ArXiv_(identifier)):[1706.02208](https://arxiv.org/abs/1706.02208). [Bibcode](/source/Bibcode_(identifier)):[2017MNRAS.471..770M](https://ui.adsabs.harvard.edu/abs/2017MNRAS.471..770M). [doi](/source/Doi_(identifier)):[10.1093/mnras/stx1433](https://doi.org/10.1093%2Fmnras%2Fstx1433). [S2CID](/source/S2CID_(identifier)) [73594365](https://api.semanticscholar.org/CorpusID:73594365).

1. **[^](#cite_ref-chandler_9-0)** Chandler, S. C. (1896). "Third catalogue of variable stars". *Astronomical Journal*. **16**: 145. [Bibcode](/source/Bibcode_(identifier)):[1896AJ.....16..145C](https://ui.adsabs.harvard.edu/abs/1896AJ.....16..145C). [doi](/source/Doi_(identifier)):[10.1086/102484](https://doi.org/10.1086%2F102484).

1. **[^](#cite_ref-pickering_10-0)** [Pickering, Edward Charles](/source/Edward_Charles_Pickering) (1905). "Second supplement to Catalogue of Variable Stars". *Annals of Harvard College Observatory*. **53**: 143–153. [Bibcode](/source/Bibcode_(identifier)):[1905AnHar..53..143P](https://ui.adsabs.harvard.edu/abs/1905AnHar..53..143P).

1. **[^](#cite_ref-koen_11-0)** Koen, Chris; Eyer, Laurent (2002). ["New periodic variables from the Hipparcos epoch photometry"](https://doi.org/10.1046%2Fj.1365-8711.2002.05150.x). *Monthly Notices of the Royal Astronomical Society*. **331** (1): 45–59. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0112194](https://arxiv.org/abs/astro-ph/0112194). [Bibcode](/source/Bibcode_(identifier)):[2002MNRAS.331...45K](https://ui.adsabs.harvard.edu/abs/2002MNRAS.331...45K). [doi](/source/Doi_(identifier)):[10.1046/j.1365-8711.2002.05150.x](https://doi.org/10.1046%2Fj.1365-8711.2002.05150.x). [S2CID](/source/S2CID_(identifier)) [10505995](https://api.semanticscholar.org/CorpusID:10505995).

1. **[^](#cite_ref-pourbaix_12-0)** Pourbaix, D.; Platais, I.; Detournay, S.; Jorissen, A.; Knapp, G.; Makarov, V. V. (2003). "How many Hipparcos Variability-Induced Movers are genuine binaries?". *Astronomy and Astrophysics*. **399** (3): 1167–1176. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0212201](https://arxiv.org/abs/astro-ph/0212201). [Bibcode](/source/Bibcode_(identifier)):[2003A&A...399.1167P](https://ui.adsabs.harvard.edu/abs/2003A&A...399.1167P). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20021843](https://doi.org/10.1051%2F0004-6361%3A20021843). [S2CID](/source/S2CID_(identifier)) [17844733](https://api.semanticscholar.org/CorpusID:17844733).

1. **[^](#cite_ref-edr3_13-0)** [Brown, A. G. A.](/source/Anthony_Brown_(scientist)); et al. (Gaia collaboration) (2021). ["*Gaia* Early Data Release 3: Summary of the contents and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202039657). *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **649**: A1. [arXiv](/source/ArXiv_(identifier)):[2012.01533](https://arxiv.org/abs/2012.01533). [Bibcode](/source/Bibcode_(identifier)):[2021A&A...649A...1G](https://ui.adsabs.harvard.edu/abs/2021A&A...649A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202039657](https://doi.org/10.1051%2F0004-6361%2F202039657). [S2CID](/source/S2CID_(identifier)) [227254300](https://api.semanticscholar.org/CorpusID:227254300). (Erratum: [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202039657e](https://doi.org/10.1051%2F0004-6361%2F202039657e)). [Gaia EDR3 record for this source](https://vizier.u-strasbg.fr/viz-bin/VizieR-S?Gaia%20EDR3%206220360697682027392) at [VizieR](/source/VizieR).

1. **[^](#cite_ref-lewis_14-0)** Lewis, B. M. (October 1997). "A renewed search for water maser emission from Mira Variables". *The Astrophysical Journal*. **114**: 1602–1606. [arXiv](/source/ArXiv_(identifier)):[astro-ph/9706207](https://arxiv.org/abs/astro-ph/9706207). [Bibcode](/source/Bibcode_(identifier)):[1997AJ....114.1602L](https://ui.adsabs.harvard.edu/abs/1997AJ....114.1602L). [doi](/source/Doi_(identifier)):[10.1086/118591](https://doi.org/10.1086%2F118591). [S2CID](/source/S2CID_(identifier)) [119386147](https://api.semanticscholar.org/CorpusID:119386147).

## Notes

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 [Y Centauri](https://en.wikipedia.org/wiki/Y_Centauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Y_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.