Gamma Coronae Borealis

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Gamma Coronae Borealis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Borealis
Right ascension 03h 47m 14.34s[1]
Declination −74° 14′ 20.3″[1]
Apparent magnitude (V) 3.84[2]
Spectral type A0V[3]

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.[4] The individual stars have visual magnitudes of 4.04 and 5.60,[5] and spectral types B9V and A3V.[6]

When discovered to be variable in 1970, it was classified as a Delta Scuti variable with the earliest known spectral type of any known at the time and an amplitude of 0.05 magnitudes,[7] but it was soon realized that the nature of its variations was likely different from other Delta Scuti variables.[8] It is now known that stars with such spectral types can have pulsations similar to those of Delta Scuti variables.[9]

References[edit]

  1. ^ a b van Leeuwen, F. (November 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. 
  2. ^ "Gamma Coronae Borealis". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 26 July 2015. 
  3. ^ 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. 
  4. ^ Kaler, James B. (25 July 2008). "Gamma Coronae Borealis". Stars. University of Illinois. Retrieved 18 November 2014. 
  5. ^ 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. 
  6. ^ 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. 
  7. ^ 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. 
  8. ^ Veto, B.; Kovacs, G. (October 1981). "Standstill of gamma CrB". Information Bulletin on Variable Stars (2030): 1. Bibcode:1981IBVS.2030....1V. 
  9. ^ 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.