Gamma Coronae Borealis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Corona Borealis |
| Right ascension | 15h 42m 44.57s[1] |
| Declination | +26° 17′ 44.3″[1] |
| Apparent magnitude (V) | 3.84[1] |
| Spectral type | A0V[2] |
Gamma Coronae Borealis (γ CrB) is a star in the constellation Corona Borealis. A spectroscopic binary system, its components orbit each other every 92.94 years and are roughly as far apart from each other as the Sun and Neptune.[3] The individual stars have visual magnitudes of 4.04 and 5.60,[4] and spectral types B9V and A3V.[5]
When discovered to be variable in 1970, it was classified as a Delta Scuti variable with the earliest known spectral type of any known variable at the time and an amplitude of 0.05 magnitudes,[6] but it was soon realized that the nature of its variations was likely different from other Delta Scuti variables.[7] It is now known that stars with such spectral types can have pulsations similar to those of Delta Scuti variables.[8]
References
- 1 2 3 "Gamma Coronae Borealis". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 26 July 2015.
- ↑ Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
- ↑ Kaler, James B. (25 July 2008). "Gamma Coronae Borealis". Stars. University of Illinois. Retrieved 18 November 2014.
- ↑ Cvetkovic, Z.; Ninkovic, S. (2010). "On the Component Masses of Visual Binaries". Serbian Astronomical Journal. 180: 71–80. Bibcode:2010SerAJ.180...71C. doi:10.2298/SAJ1080071C.
- ↑ Malkov, O. Yu.; Tamazian, V.S.; Docobo, J.A.; Chulkov, D.A. (2012). "Dynamical masses of a selected sample of orbital binaries". Astronomy & Astrophysics. 546: 5. Bibcode:2012A&A...546A..69M. doi:10.1051/0004-6361/201219774. A69.
- ↑ Percy, John R. (February 1970). "The Light Variation of γ Coronae Borealis". Publications of the Astronomical Society of the Pacific. 82: 126. Bibcode:1970PASP...82..126P. doi:10.1086/128893.
- ↑ Veto, B.; Kovacs, G. (October 1981). "Standstill of gamma CrB". Information Bulletin on Variable Stars (2030): 1. Bibcode:1981IBVS.2030....1V.
- ↑ Lehmann, H.; Scholz, G.; Hildebrandt, G.; Yang, S. (November 1997). "The RV-variations of γ Coronae Borealis - a frequency analysis". Astronomy and Astrophysics. 327: 167–172. Bibcode:1997A&A...327..167L.