RV Caeli

RV Caeli is a red giant star in the constellation Caelum. With an apparent magnitude of 6.4, it's barely visible to the naked eye, but this can vary. RV Caeli has a high radial velocity, which means it's moving away from the Solar System, and is currently located 1,200 light-years (370 pc) away using parallax.

RV Caeli
Location of RV Caeli (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Caelum
Right ascension 04h 28m 09.4637s[1]
Declination −41° 57′ 35.396″[1]
Apparent magnitude (V) 6.41[2]
Characteristics
Spectral type M1III[3]
Variable type semiregular[4]
Astrometry
Radial velocity (Rv)97.90±0.30[1] km/s
Proper motion (μ) RA: −14.75±0.37 mas/yr[5]
Dec.: 2.87±0.40 mas/yr[5]
Parallax (π)2.7124 ± 0.0633 mas[1]
Distance1,200 ± 30 ly
(369 ± 9 pc)
Absolute magnitude (MV)−1.36[2]
Details
Mass1.14[6] M☉
Radius65.57[7] R☉
Luminosity975[7] L☉
Surface gravity (log g)0.67[6] cgs
Temperature3984[7] K
Other designations
CD−42°1510, HD 28552, HIP 20856, HR 1429, SAO 216821
Database references
SIMBADdata

Properties

This star is a red giant who has exhausted hydrogen at its core. It has a similar mass to the Sun, but has ballooned to 65 times the radius. It a very luminous star, with a luminosity about 1,000 times greater than our Sun. RV Caeli has a cool effective temperature of 3,984 K, which gives it a red hue. It is considered to be on the asymptotic giant branch, having exhausted its core hydrogen and helium.[8]

Variability
A visual band light curve for RV Caeli, adapted from Tabur et al. (2009).[9]

Hipparcos has found it to vary between its photometric values of 6.44 and 6.56,[4] which roughly corresponds with the magnitude as seen with the naked eye. It was first suspected of variability in 1970.[10] A 1982 survey again identified suspected variations, but could not confirm it was a variable star.[11] It was confirmed as a variable star in 1999 on the basis of the Hipparcos photometry and given the variable star designation RV Caeli.[12]

References
  1. Gaia Collaboration (2018-04-01). "VizieR Online Data Catalog: Gaia DR2 (Gaia Collaboration, 2018)". VizieR Online Data Catalog. 1345. Bibcode:2018yCat.1345....0G.
  2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. Houk, Nancy (1978). "Michigan catalogue of two-dimensional spectral types for the HD stars". Ann Arbor: Dept. Of Astronomy, University of Michigan. 2. Bibcode:1978MSS...C02....0H.
  4. VSX (25 August 2009). "RV Cae". International Variable Star Index. American Association of Variable Star Observers. Retrieved 30 June 2014.
  5. van Leeuwen, F. (2007-11-01). "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. ISSN 0004-6361. S2CID 18759600.
  6. Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevic, G.; Monari, G.; Cantat-Gaudin, T. (2019-08-01). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. S2CID 131780028.
  7. Gaia Collaboration; Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; Babusiaux, C.; Bailer-Jones, C. A. L.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F. (2018-08-01). "Gaia Data Release 2. Summary of the contents and survey properties". Astronomy and Astrophysics. 616: A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. ISSN 0004-6361. S2CID 49211658.
  8. Eggen, Olin J. (July 1992). "Asymptotic giant branch stars near the sun". Astronomical Journal. 104 (1): 275–313. Bibcode:1992AJ....104..275E. doi:10.1086/116239.
  9. Tabur, V.; Bedding, T. R.; Kiss, L. L.; Moon, T. T.; Szeidl, B.; Kjeldsen, H. (December 2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945–1961. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. S2CID 15358380. Retrieved 8 November 2021.
  10. Eggen, O. J.; Stokes, N. R. (1970). "Narrow-Band and Broad-Band Photometry of Red Stars. III. Southern Giants". The Astrophysical Journal. 161: 199. Bibcode:1970ApJ...161..199E. doi:10.1086/150525.
  11. Rufener, F.; Bartholdi, P. (1982). "List of 333 variable, microvariable or suspected variable stars detected in the Geneva photometry". Astronomy and Astrophysics Supplement Series. 48: 503. Bibcode:1982A&AS...48..503R.
  12. Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars. 4659: 1. Bibcode:1999IBVS.4659....1K.
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