Xi Coronae Borealis

Xi Coronae Borealis (ξ CrB) is a binary star[3] system in the northern constellation of Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of 4.85.[2] Based upon an annual parallax shift of 17.78 mas as seen from the Earth,[1] it is located about 183 light years from the Sun.

Xi Coronae Borealis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Borealis
Right ascension  16h 22m 05.82391s[1]
Declination +30° 53′ 31.1837″[1]
Apparent magnitude (V) 4.85[2]
Characteristics
Spectral type K0 III[3]
U−B color index +0.80[2]
B−V color index +0.97[2]
Astrometry
Radial velocity (Rv)−29.20±0.16[4] km/s
Proper motion (μ) RA: −97.43[1] mas/yr
Dec.: +107.45[1] mas/yr
Parallax (π)17.78 ± 0.25[1] mas
Distance183 ± 3 ly
(56.2 ± 0.8 pc)
Absolute magnitude (MV)+1.04[5]
Details[4]
Mass2.36[5] M☉
Radius8 R☉
Luminosity36 L☉
Surface gravity (log g)2.9 cgs
Temperature4,853±5 K
Metallicity [Fe/H]−0.08 dex
Rotational velocity (v sin i)2.8 km/s
Age676[5] Myr
Other designations
ξ CrB, 19 CrB, BD+31° 2845, HD 147677, HIP 80181, HR 6103, SAO 65254, WDS J16221+3054A[6]
Database references
SIMBADdata

As of 2009, the pair had an angular separation of 91 mas along a position angle of 139.4°.[7] The brighter member, component Aa,[7] is an evolved K-type giant star with a stellar classification of K0 III.[3] It is a red clump star that is generating energy by helium fusion at its core.[8] The star has an estimated 2.36 times the mass of the Sun and has expanded to 8 times the Sun's radius. It is radiating 36 times the solar luminosity from its photosphere at an effective temperature of 4,853 K.[4]

References
  1. 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.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
  3. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  4. Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  5. Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781.
  6. "ksi CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-05-03.
  7. Hartkopf, William I.; Mason, Brian D. (2009), "Speckle Interferometry at Mount Wilson Observatory: Observations Obtained in 2006-2007 and 35 New Orbits", The Astronomical Journal, 138 (3): 813, Bibcode:2009AJ....138..813H, doi:10.1088/0004-6256/138/3/813.
  8. Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278.
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