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V553 Centauri

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V553 Centauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus[1]
Right ascension 14h 46m 33.636s[2]
Declination −32° 10′ 15.27″[2]
Apparent magnitude (V) 8.48[1] (8.22 to 8.80)[3]
Characteristics
Spectral type G5p I–III[4]
B−V color index 0.600±0.020[1]
Variable type BL Her[3]
Astrometry
Radial velocity (Rv)−4.95±3.95[2] km/s
Proper motion (μ) RA: 4.145 mas/yr[2]
Dec.: −1.914 mas/yr[2]
Parallax (π)1.7286 ± 0.0224 mas[2]
Distance1,890 ± 20 ly
(579 ± 7 pc)
Details
Mass0.49[5] M☉
Radius9.9[5] R☉
Surface gravity (log g)2.2[6] cgs
Temperature6,060[6] K
Metallicity [Fe/H]0.01[6] dex
Other designations
V553 Cen, CD−31° 11449, HD 129981, HIP 72257, SAO 205930, PPM 293050[7]
Database references
SIMBADdata

V553 Centauri is a variable star in the southern constellation of Centaurus, abbreviated V553 Cen. It ranges in brightness from an apparent visual magnitude of 8.22 down to 8.80 with a period of 2.06 days.[3] At that magnitude, it is too dim to be visible to the naked eye. Based on parallax measurements,[2] it is located at a distance of approximately 1,890 light years from the Sun.

Observations

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A light curve for V553 Centauri, plotted from TESS data[8]

The variability of this star was announced in 1936 by C. Hoffmeister.[9] In 1957, he determined it to be a Delta Cepheid variable with a magnitude range of 8.3 to 8.6 and a periodicity of 2.06119 d. The observers M. W. Feast and G. H. Herbig noted a peculiar spectrum with strong absorption lines of the molecules CH and CN, while neutral iron lines are unusually weak. They found a stellar classification of G5p I–III.[4]

In 1972, T. Lloyd-Evans and associates found the star's prominent bands of C2, CH, and CN varied with the Cepheid phase, being strongest at minimum. They suggested a large overabundance of carbon in the star's atmosphere.[10] Chemical analysis of the atmosphere in 1979 showed a metallicity close to solar, with an enhancement of carbon and nitrogen. It was proposed that V553 Cen is an evolved RR Lyrae variable and is now positioned above the horizontal branch on the HR diagram.[11] V553 Cen is classified as a BL Herculis variable, being a low–mass type II Cepheid with a period between 1 to 6 d. As with other variables of this type, it displays a secondary bump on its light curve.[5] It is a member of a small group of carbon Cepheids, and is one of the brightest stars of that type.[12]

V553 Cen does not appear to have a companion.[13] From the luminosity and shape of the light curve, stellar models from 1981 suggest a mass equal to 49% of the Sun's with 9.9 times the radius of the Sun.[5] Further analysis of the spectrum showed that oxygen is not enhanced, but sodium may be moderately enhanced.[12] There is no evidence of s-process enhancement of elements. Instead, the abundance peculiarities are the result of nuclear reaction sequences followed by dredge-up.[13] In particular, these are the product of triple-α, CN, ON, and perhaps some Ne–Na reactions.[12]

See also

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References

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  1. ^ a b c 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.
  2. ^ a b c d e f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b c Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 255195566.
  4. ^ a b Hoffmeister, Cuno (May 1957), "On Two Abnormal Stars of Delta Cephei Type", Astrophysical Journal, 125: 824, Bibcode:1957ApJ...125..824H, doi:10.1086/146358.
  5. ^ a b c d Petersen, J. O. (March 1981), "V553 Centauri and a progression of bumps in BL Herculis light curves", Astronomy and Astrophysics, 96: 146–150, Bibcode:1981A&A....96..146P.
  6. ^ a b c Kovtyukh, V.; et al. (May 2018), "Metal-poor Type II Cepheids with Periods Less Than Three Days", Publications of the Astronomical Society of the Pacific, 130 (987), arXiv:1803.05041, Bibcode:2018PASP..130e4201K, doi:10.1088/1538-3873/aaacf7.
  7. ^ "V553 Cen", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2024-12-31.
  8. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 5 January 2025.
  9. ^ Hoffmeister, Cuno (April 1936), "71 südlicheneue Veränderliche", Astronomische Nachrichten (in German), 258 (3): 39, Bibcode:1936AN....258...39H, doi:10.1002/asna.19362580303.
  10. ^ Lloyd Evans, T.; et al. (1972), "V553 Centauri: a type II cepheid with an overabundance of carbon", Monthly Notices of the Royal Astronomical Society, 159: 67, Bibcode:1972MNRAS.159...67L, doi:10.1093/mnras/159.1.67.
  11. ^ Cotrell, P. L. (October 1979), "Carbon and nitrogen abundances in the carbon-rich Cepheid V553 Centauri", Monthly Notices of the Royal Astronomical Society, 189: 13–25, Bibcode:1979MNRAS.189...13C, doi:10.1093/mnras/189.1.13.
  12. ^ a b c d Wallerstein, George; Gonzalez, Guillermo (October 1996), "The carbon Cepheid V553 Cen: evidence of triple-alpha and CNO cycling", Monthly Notices of the Royal Astronomical Society, 282 (4): 1236–1246, Bibcode:1996MNRAS.282.1236W, doi:10.1093/mnras/282.4.1236.
  13. ^ a b Wallerstein, G.; Gonzalez, G. (1998), Bradley, Paul A.; Guzik, Joyce A. (eds.), "V553 Cen and the Carbon Cepheids", A Half Century of Stellar Pulsation Interpretation: A Tribute to Arthur N. Cox; proceedings of a Conference held in Los Alamos, NM 16-20 June 1997, ASP Conference Series, vol. 135, p. 36, Bibcode:1998ASPC..135...36W.

Further reading

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