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. It is 480±10 light-years distant from Earth.
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux[1] |
| Right ascension | 12h 27m 28.88s[2] |
| Declination | −58° 59′ 30.4″[2] |
| Apparent magnitude (V) | 5.43[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | M4/5III[5] |
| Variable type | SR[3] |
| Astrometry | |
| Radial velocity (Rv) | 71.7±0.9[6] km/s |
| Proper motion (μ) | RA: −19.294[2] mas/yr Dec.: +4.680[2] mas/yr |
| Parallax (π) | 6.8429±0.1942 mas[2] |
| Distance | 480 ± 10 ly (146 ± 4 pc) |
| Absolute magnitude (MV) | −0.28[1] |
| Details | |
| Mass | 3.6[7] M☉ |
| Radius | 106[8] R☉ |
| Luminosity | 1,234[8] L☉ |
| Surface gravity (log g) | 1.94[7] cgs |
| Temperature | 3,320[8] K |
| Metallicity [Fe/H] | −0.33[7] dex |
| Other designations | |
| CD−58°4560, HD 108396, HIP 60781, HR 4739, SAO 239960[9] | |
| Database references | |
| SIMBAD | data |
In 1969, Olin J. Eggen announced that the star, then called HR 4739, is a variable star.[11] It was given its variable star designation, BL Crucis, in 1977.[12] Three periods have been detected in its light curve, 30.7, 42.3 and 43.6 days.[10] The maximum amplitude of variation is 0.35 magnitudes.[3]
An aging red giant, BL Crucis is on the asymptotic giant branch having exhaust both its core hydrogen and core helium. It now fuses hydrogen and helium in separate shells outside the core.[4]
References
edit- ^ a b 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. XHIP record for this object at VizieR.
- ^ a b c d e 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.
- ^ a b c Watson, Christopher (25 August 2009). "BL Crucis". International Variable Star Index. AAVSO. Retrieved 20 July 2014.
- ^ a b Eggen, Olin J. (1992). "Asymptotic Giant Branch Stars Near the Sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239.
- ^ Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations -90_ to -53_ƒ0. Bibcode:1975mcts.book.....H.
- ^ Evans, D. S. (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications. 30: 57. Bibcode:1967IAUS...30...57E.
- ^ a b c Khalatyan, A.; Anders, F.; Chiappini, C.; Queiroz, A. B. A.; Nepal, S.; Dal Ponte, M.; Jordi, C.; Guiglion, G.; Valentini, M.; Torralba Elipe, G.; Steinmetz, M.; Pantaleoni-González, M.; Malhotra, S.; Jiménez-Arranz, Ó.; Enke, H.; Casamiquela, L.; Ardèvol, J. (2024). "Transferring spectroscopic stellar labels to 217 million Gaia DR3 XP stars with SHBoost". Astronomy and Astrophysics. 691: A98. arXiv:2407.06963. Bibcode:2024A&A...691A..98K. doi:10.1051/0004-6361/202451427.
- ^ a b c Fetherolf, Tara; Pepper, Joshua; Simpson, Emilie; Kane, Stephen R.; Močnik, Teo; English, John Edward; Antoci, Victoria; Huber, Daniel; Jenkins, Jon M.; Stassun, Keivan; Twicken, Joseph D.; Vanderspek, Roland; Winn, Joshua N. (2023). "Variability Catalog of Stars Observed during the TESS Prime Mission". The Astrophysical Journal Supplement Series. 268 (1): 4. arXiv:2208.11721. Bibcode:2023ApJS..268....4F. doi:10.3847/1538-4365/acdee5.
- ^ "BL Crucis". SIMBAD. Centre de données astronomiques de Strasbourg.
- ^ a b 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.
- ^ 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
edit- David H. Levy, Observing variable stars : a guide for the beginner ISBN 0521627559
- General Catalogue of Variable Stars