R Centauri

R Centauri (R Cen) is a Mira variable star in the constellation Centaurus. It is approximately 1,300 light years from Earth.

For r Centauri, see HD 115310.
R Centauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 14h 16m 34.321s[1]
Declination −59° 54′ 49.29″[1]
Apparent magnitude (V) 5.2 - 11.5[2]
Characteristics
Spectral type M5IIe[3] (M4e-M9.5[2])
U−B color index +1.24[4]
B−V color index +2.04[4]
Variable type Mira[2]
Astrometry
Radial velocity (Rv)−19.8[5] km/s
Proper motion (μ) RA: -9.07 ± 0.91[1] mas/yr
Dec.: -7.04 ± 0.71[1] mas/yr
Parallax (π)2.60 ± 0.76[1] mas
Distanceapprox. 1,300 ly
(approx. 400 pc)
Absolute magnitude (MV)−1.49 (at maximum)[6]
Details
Luminosity47,000[3] L☉
Temperature3,450[3] K
Other designations
R Centauri, HR 5326, HD 124601, CP−59°5476, HIP 69754, SAO 241580, GC 19234, CCDM J14166-5955
Database references
SIMBADdata

R Centauri is a Mira variable and its brightness varies from magnitude +5.2 to +11.5 with a period of about 500 days. It used to have an unusual double-peaked light curve, but by 2001 this had reverted to an almost normal single-peaked curve. Prior to 1950 the period was about 550 days, but since then has decreased to about 500 days. A 2016 analysis of ASAS data derived a period of 498.84 days.[7]

It is thought that the unusual behaviour of R Centauri is caused by a flash in the helium shell around its core, which occurs periodically in asymptotic giant branch (AGB) stars as the mass of the helium shell increases with helium from the outer hydrogen shell.[8]

It is also an H2O maser source.[9]

References
  1. 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. Vizier catalog entry
  2. 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. Bibcode:2009yCat....102025S.
  3. Verhoelst, T; Van Der Zypen, N; Hony, S; Decin, L; Cami, J; Eriksson, K (2009). "The dust condensation sequence in red supergiant stars". Astronomy & Astrophysics. 498 (1): 127–138. arXiv:0901.1262. Bibcode:2009A&A...498..127V. doi:10.1051/0004-6361/20079063. S2CID 18383796.
  4. Hoffleit, Dorrit; Jaschek, Carlos (1991). "The Bright star catalogue". New Haven. Bibcode:1991bsc..book.....H.
  5. Wilson, R.E (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  6. Celis s, L. (1986). "Spectral and luminosity variation of long-period red variable stars". The Astronomical Journal. 91: 405. Bibcode:1986AJ.....91..405C. doi:10.1086/114019.
  7. Vogt, N; Contreras-Quijada, A; Fuentes-Morales, I; Vogt-Geisse, S; Arcos, C; Abarca, C; Agurto-Gangas, C; Caviedes, M; Dasilva, H; Flores, J; Gotta, V; Peñaloza, F; Rojas, K; Villaseñor, J. I (2016). "Determination of Pulsation Periods and Other Parameters of 2875 Stars Classified As Mira in the All Sky Automated Survey (Asas)". The Astrophysical Journal Supplement Series. 227 (1): 6. arXiv:1609.05246. Bibcode:2016ApJS..227....6V. doi:10.3847/0067-0049/227/1/6. S2CID 119295645.
  8. Hawkins, G; Mattei, J. A; Foster, G (2001). "R Centauri: An Unusual Mira Variable in a He‐Shell Flash". Publications of the Astronomical Society of the Pacific. 113 (782): 501. Bibcode:2001PASP..113..501H. doi:10.1086/319542.
  9. Lepine, J.R.D.; Paes de Barros, M.H. (1977). "Characteristics of the H2O emission from Mira variables". Astronomy and Astrophysics. 56: 219–226. Bibcode:1977A&A....56..219L.
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