Y Centauri

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This article is about Y Centauri. For y Centauri, see HD 120987. For γ Centauri, see Gamma Centauri.
Y Centauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 14h 30m 58.61656s[1]
Declination −30° 05′ 51.8706″[1]
Apparent magnitude (V) +8.90[2]
Spectral type M4e - M7[3]
U−B color index +0.72[2]
B−V color index +1.44[2]
Variable type SRb[3]
Radial velocity (Rv) −6.00[4] km/s
Proper motion (μ) RA: −39.66[1] mas/yr
Dec.: −25.92[1] mas/yr
Parallax (π) 3.50 ± 0.93[1] mas
Distance approx. 900 ly
(approx. 290 pc)
Luminosity 5,317[5] L
Temperature 2,907[5] K
Other designations
Y Cen, HD 127233, BD−29°11116, HIP 70969, SAO 182618, GC 19563, IRAS 14280-2952, AAVSO 1425-29
Database references

Y Centauri or Y Cen (HD 127233, HIP 70969) is a semiregular variable star in the constellation of Centaurus.

The variability in the star was discovered by 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".[6] It was later given the designation HV 52 in the Harvard Catalogue of Variable Stars.[7] The General Catalogue of Variable Stars lists it as a possible semiregular variable star with a period of 180 days and a photographic magnitude range of 8.9 - 10.0.[3] A study of Hipparcos satellite photometry found a small amplitude range of 0.2 magnitudes at a visual magnitude of 8.53.[8]

The distance of the star is poorly known. The revised Hipparcos annual parallax of 3.50 mas gives a distance of 900 light years.[1] 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.[9] It is an asymptotic giant branch[10] star over five thousand 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 emission,[11] although later searches did not find any maser emission.[10]


  1. ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752free to read. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c 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:2002yCat.2237....0D. 
  3. ^ a b c d 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:2009yCat....102025S. 
  4. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. 
  5. ^ a b McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427: 343. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. 
  6. ^ Chandler, S. C. (1896). "Third catalogue of variable stars". Astronomical Journal. 16: 145. Bibcode:1896AJ.....16..145C. doi:10.1086/102484. 
  7. ^ Pickering, Edward Charles (1905). "Second supplement to Catalogue of Variable Stars". Annals of Harvard College Observatory. 53: 143–153. Bibcode:1905AnHar..53..143P. 
  8. ^ Koen, Chris; Eyer, Laurent (2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society. 331: 45. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x. 
  9. ^ 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. Bibcode:2003A&A...399.1167P. doi:10.1051/0004-6361:20021843. 
  10. ^ a b 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". The Astrophysical Journal Supplement. 211: 15. Bibcode:2014ApJS..211...15Y. doi:10.1088/0067-0049/211/1/15. 
  11. ^ Lewis, B. M. (October 1997). "A renewed search for water maser emission from Mira Variables". The Astrophysical Journal. 114: 1602–1606. arXiv:astro-ph/9706207free to read. Bibcode:1997AJ....114.1602L. doi:10.1086/118591.