V810 Centauri is a double star consisting of a yellow hypergiant[3] primary (V810 Cen A) and blue giant secondary (V810 Cen B). It is a small amplitude variable star, entirely due to the supergiant primary which is visually over three magnitudes (about 12x) brighter than the secondary.[6] It is the MK spectral standard for class G0 0-Ia.[3] A 5th magnitude star, it is visible to the naked eye under good observing conditions.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 11h 43m 31.193s[2] |
| Declination | –62° 29′ 21.82″[2] |
| Apparent magnitude (V) | 5.021var[1] |
| Characteristics | |
| Spectral type | G0 0-Ia[3] (F8Ia + B0III[1]) |
| U−B color index | 1.762[1] |
| B−V color index | 0.014[1] |
| Variable type | SRd[4] |
| Astrometry | |
| Radial velocity (Rv) | 16.44[5] km/s |
| Proper motion (μ) | RA: –5.74 ± 0.21[2] mas/yr Dec.: 1.30 ± 0.17[2] mas/yr |
| Parallax (π) | 0.46 ± 0.22 mas[2] |
| Distance | 3,300 - 3,500[1] pc |
| Absolute magnitude (MV) | -8.4/-5.1[1] |
| Details[1] | |
| Mass | 20/25 M☉ |
| Radius | 420/14 R☉ |
| Luminosity | 200,000/125,000 L☉ |
| Surface gravity (log g) | 0.7/3.5 cgs |
| Temperature | 6,010/29,000 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Maurice Pim FitzGerald announced that the star's brightness varies, in 1973.[7] It was given its variable star designation, V810 Centauri, in 1979.[8] V810 Cen A shows semi-regular variations with several component periods. The dominant mode is around 156 days and corresponds to Cepheid fundamental mode radial pulsation. Without the other stellar pulsation modes it would be considered a Classical Cepheid variable. Other pulsation modes have been detected at 89 to 234 days, with the strongest being a possible non-radial p-mode at 107 days and a possible non-radial g-mode at 185 days.[1]
The blue giant secondary has a similar mass and luminosity to the supergiant primary, but is visually much fainter. The primary is expected to have lost around 5 M☉ since it was on the main sequence, and has expanded and cooled so it lies at the blue edge of the Cepheid instability strip. It is expected to get no cooler and may perform a blue loop while slowly increasing in luminosity.[1]
V810 Cen was once thought to be a member of the Stock 14 open cluster at 2.6 kpc,[9] but now appears to be more distant. The distance derived from spectrophotometric study is larger than the mean Hipparcos parallax value but within the margin of error.
References
edit- ^ a b c d e f g h i j Kienzle, F.; Burki, G.; Burnet, M.; Meynet, G. (1998). "The pulsating yellow supergiant V810 Centauri". Astronomy and Astrophysics. 337: 779. arXiv:astro-ph/9807088. Bibcode:1998A&A...337..779K.
- ^ a b c d e 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 Garcia, B. (1989). "A list of MK standard stars". Bulletin d'Information du Centre de Données Stellaires. 36: 27. Bibcode:1989BICDS..36...27G.
- ^ 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.
- ^ Mermilliod, J. C.; Mayor, M.; Udry, S. (2008). "Red giants in open clusters. XIV. Mean radial velocities for 1309 stars and 166 open clusters". Astronomy and Astrophysics. 485 (1): 303–314. Bibcode:2008A&A...485..303M. CiteSeerX 10.1.1.30.7545. doi:10.1051/0004-6361:200809664.
- ^ Eichendorf, W.; Lub, J.; Pakull, M.; Heck, A.; Isserstedt, J.; Reipurth, B.; Van Genderen, A. M. (1981). "On the nature of the 125-day Cepheid V 810 CEN /equals HR 4511/ - IUE spectra". Astronomy and Astrophysics. 93: L5. Bibcode:1981A&A....93L...5E.
- ^ Fitzgerald, M. P. (March 1973). "Error analysis of the photoelectric catalogue". Astronomy and Astrophysics Supplement: 297–311. Bibcode:1973A&AS....9..297F. Retrieved 22 December 2024.
- ^ Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (April 1979). "64th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1581: 1–8. Bibcode:1979IBVS.1581....1K. Retrieved 22 December 2024.
- ^ Turner, D. G. (1982). "New UBV photometry for the open cluster Stock 14 and its Cepheid-like variable V810 Centauri /= HR 4511/". Publications of the Astronomical Society of the Pacific. 94: 655. Bibcode:1982PASP...94..655T. doi:10.1086/131039.