Nu1 Coronae Borealis

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Nu1 Coronae Borealis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Borealis
Right ascension 16h 22m 21.42498s[1]
Declination +33° 47′ 56.5893″[1]
Apparent magnitude (V) 5.20[2]
Spectral type M2 III[3]
B−V color index 1.64[3]
Radial velocity (Rv)−13.17±0.35[4] km/s
Proper motion (μ) RA: +4.97[1] mas/yr
Dec.: −37.92[1] mas/yr
Parallax (π)5.09 ± 0.22[1] mas
Distance640 ± 30 ly
(196 ± 8 pc)
Absolute magnitude (MV)−1.19[3]
Radius67.1±7.1[5] R
Luminosity1,155[6] L
Temperature3,760[6] K
Other designations
η1 CrB, 20 CrB, BD+34° 2773, HD 147749, HIP 80197, HR 6107, SAO 65257[7]
Database references

Nu1 Coronae Borealis is a solitary,[8] red-hued star located in the constellation Corona Borealis. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.20.[2] Based upon an annual parallax shift of 5.09 mas,[1] it is located roughly 640 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.1 due to interstellar dust.[9]

This is an evolved red giant star with a stellar classification of M2 III.[3] It is a variable star of uncertain type, showing a change in brightness with an amplitude of 0.0114 magnitude and a frequency of 0.22675 cycles per day, or 4.41 days/cycle.[10] It has about 67[5] times the Sun's radius and is radiating 1,155 times the Sun's luminosity from its photosphere at an effective temperature of 3,760 K.[6]


  1. ^ a b c d e f 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. ^ a b Ducati, J. R. (2002), "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system", CDS/ADC Collection of Electronic Catalogues, 2237, Bibcode:2002yCat.2237....0D.
  3. ^ a b c d Huang, W.; et al. (2012), "A catalogue of Paschen-line profiles in standard stars", Astronomy & Astrophysics, 547: A62, arXiv:1210.7893, Bibcode:2012A&A...547A..62H, doi:10.1051/0004-6361/201219804.
  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, A61.
  5. ^ a b Dyck, H. M.; Benson, J. A.; Van Belle, G. T.; Ridgway, S. T. (1996), "Radii and Effective Temperatures for K and M Giants and Supergiants", The Astronomical Journal, 111 (1): 521–533, Bibcode:1996AJ....111.1705D, doi:10.1086/117910.
  6. ^ a b c 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.
  7. ^ "nu01 CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-26.
  8. ^ 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.
  9. ^ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272.
  10. ^ Koen, Chris; Eyer, Laurent (2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331: 45, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x.