Upsilon Coronae Borealis

Upsilon Coronae Borealis, Latinized from υ Coronae Borealis, is a solitary[10] star in the northern constellation of Corona Borealis. It is a white-hued star that is dimly visible to the naked eye with an apparent visual magnitude of 5.78.[2] The distance to this object is approximately 630 light-years (190 parsecs) based on parallax.[1]

Upsilon Coronae Borealis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Borealis
Right ascension 16h 16m 44.78733s[1]
Declination +29° 09′ 00.9399″[1]
Apparent magnitude (V) 5.78[2]
Characteristics
Spectral type A3V[3]
U−B color index +0.10[2]
B−V color index +0.07[2]
Astrometry
Radial velocity (Rv)0.8±1.0[4] km/s
Proper motion (μ) RA: +23.474[1] mas/yr
Dec.: −16.644[1] mas/yr
Parallax (π)5.1783 ± 0.0777[1] mas
Distance630 ± 9 ly
(193 ± 3 pc)
Absolute magnitude (MV)−0.72[5]
Details
Mass3.06±0.19[6] M☉
Radius1.5[7] R☉
Luminosity151[8] L☉
Temperature8,098[8] K
Rotational velocity (v sin i)112[3] km/s
Other designations
υ CrB, 18 Coronae Borealis, NSV 7596, BD+29°2803, FK5 3287, HD 146738, HIP 79757, HR 6074, SAO 84281, WDS J16167+2909[9]
Database references
SIMBADdata

This is an A-type main-sequence star with a stellar classification of A3V;[3] a star that is currently fusing its core hydrogen. However, Palmer et al. (1968) had it classed as type A2IV,[11] and thus it may be near or past its main sequence lifetime.[6] It is a suspected variable star of unknown type that has been measured ranging in brightness from magnitude 5.78 down to 5.88.[12]

Upsilon Coronae Borealis has three[6] times the mass of the Sun and about 1.5[7] times the Sun's radius. It is spinning with a projected rotational velocity of 112 km/s.[3] The star is radiating 151[8] times the luminosity of the Sun from its photosphere at an effective temperature of 8,098 K.[8]

References
  1. 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.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  5. 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, S2CID 119257644.
  6. Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  7. Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (3rd ed.), 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  8. McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
  9. "ups CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-04-25.
  10. 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, S2CID 14878976.
  11. Palmer, D. R.; et al. (1968), "The radial velocities spectral types and projected rotational velocities of 633 bright northern A stars", Royal Observatory Bulletin, 135: 385, Bibcode:1968RGOB..135..385P.
  12. Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
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