Y Centauri or Y Cen (HD 127233, HIP 70969) is a semiregular variable star in the constellation of Centaurus.
| 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 | |
| Spectral type | M4e - M7[3] |
| U−B color index | +0.72[4] |
| B−V color index | +1.44[4] |
| Variable type | SRb[3] |
| Astrometry | |
| Radial velocity (Rv) | −6.00[5] km/s |
| Proper motion (μ) | RA: −38.874[6] mas/yr Dec.: −25.867[6] mas/yr |
| Parallax (π) | 4.4510 ± 0.2738 mas[6] |
| Distance | 730 ± 50 ly (220 ± 10 pc) |
| Details | |
| Radius | 48[6] R☉ |
| Luminosity | 330[6] L☉ |
| Surface gravity (log g) | −0.315[7] cgs |
| Temperature | 3,557[6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
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".[8] It was later given the designation HV 52 in the Harvard Catalogue of Variable Stars.[9] The 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 photometry found a small amplitude range of 0.2 magnitudes at a visual magnitude of 8.53.[10]
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.[11] Both estimates have a margin of error over 20%. The 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.[6] Gaia EDR3 does not list a parallax for this star.[12]
Y Centauri is an asymptotic giant branch[13] star 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 emission,[14] although later searches did not find any maser emission.[13]
References
edit- ^ "ASAS All Star Catalogue". The All Sky Automated Survey. Retrieved 8 December 2021.
- ^ a b c Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ a b c d e 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.
- ^ a b 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.
- ^ 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:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ a b c d e f g Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. S2CID 73594365.
- ^ Chandler, S. C. (1896). "Third catalogue of variable stars". Astronomical Journal. 16: 145. Bibcode:1896AJ.....16..145C. doi:10.1086/102484.
- ^ Pickering, Edward Charles (1905). "Second supplement to Catalogue of Variable Stars". Annals of Harvard College Observatory. 53: 143–153. Bibcode:1905AnHar..53..143P.
- ^ Koen, Chris; Eyer, Laurent (2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society. 331 (1): 45–59. arXiv:astro-ph/0112194. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x. S2CID 10505995.
- ^ 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:astro-ph/0212201. Bibcode:2003A&A...399.1167P. doi:10.1051/0004-6361:20021843. S2CID 17844733.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ 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 (1): 15. Bibcode:2014ApJS..211...15Y. doi:10.1088/0067-0049/211/1/15. S2CID 73561291.
- ^ Lewis, B. M. (October 1997). "A renewed search for water maser emission from Mira Variables". The Astrophysical Journal. 114: 1602–1606. arXiv:astro-ph/9706207. Bibcode:1997AJ....114.1602L. doi:10.1086/118591. S2CID 119386147.