 A light curve for BL Crucis, adapted from Tabur et al. (2009) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux |
| Right ascension | 12 27 28.88 |
| Declination | −58° 59′ 30.4″ |
| Apparent magnitude (V) | 5.38 |
| Characteristics | |
| Spectral type | M4-5III |
| Variable type | semiregular variable |
| Astrometry | |
| Radial velocity (Rv) | 71.7 ± 0.9 km/s |
| Proper motion (μ) | RA: -20.027 ± 0.301 mas/yr Dec.: 3.586 ± 0.268 mas/yr |
| Parallax (π) | 6.8429 ± 0.1942 mas |
| Distance | 480 ± 10 ly (146 ± 4 pc) |
| Other designations | |
| HD 108396, HIP 60781, HR 4739, SAO 239960, CD−58° 4560 | |
| Database references | |
| SIMBAD | data |
BL Crucis is a red giant and a semiregular variable in the constellation of Crux. A 5th magnitude star, it is visible to the naked eye under good observing conditions. Three periods have been detected in its light curve, 30.7, 42.3 and 43.6 days. It is 480 ± 10 light-years distant from Earth.
In 1969, Olin J. Eggen announced that the star, then called HR 4739, is a variable star. It was given its variable star designation, BL Crucis, in 1977.
References
- ^ Tabur, V.; Bedding, T. R. (2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945–61. arXiv:0908.3228. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. S2CID 15358380.
- ^ 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.
- Watson, Christopher (25 August 2009). "BL Crucis". AAVSO Website. American Association of Variable Star Observers. Retrieved 20 July 2014.
- Eggen, O. J. (June 1969). "Light Variations of Small Amplitude in the Red Giants of the Disc Population" (PDF). Information Bulletin on Variable Stars. 355. Bibcode:1969IBVS..355....1E. Retrieved 9 December 2024.
- Kukarkin, B. V.; Kholopov, P. N.; Fedorovich, V. P.; Kireyeva, N. N.; Kukarkina, N. P.; Medvedeva, G. I.; Perova, N. B. (March 1977). "62nd Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1248: 1–25. Bibcode:1977IBVS.1248....1K. Retrieved 9 December 2024.
External links
- David H. Levy, Observing variable stars : a guide for the beginner ISBN 0521627559
- General Catalogue of Variable Stars
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