Mu Coronae Borealis

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Mu Coronae Borealis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Borealis
Right ascension 15h 35m 14.91848s[1]
Declination +39° 00′ 36.2473″[1]
Apparent magnitude (V) 5.12[2]
Spectral type M1.5 IIIb[3]
U−B color index +2.01[2]
B−V color index +1.64[2]
Radial velocity (Rv) −13.17±0.35[4] km/s
Proper motion (μ) RA: +24.45[1] mas/yr
Dec.: +9.22[1] mas/yr
Parallax (π) 5.27 ± 0.24[1] mas
Distance 620 ± 30 ly
(190 ± 9 pc)
Absolute magnitude (MV) −1.25[5]
Luminosity 932[6] L
Temperature 3,889[6] K
Other designations
μ CrB, 6 CrB, BD+34° 2773, HD 139153, HIP 76307, HR 5800[7]
Database references

Mu Coronae Borealis, Latinized from μ Coronae Borealis, is a solitary,[8] rudy-hued star located in the northern constellation of Corona Borealis. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.12.[2] Based upon an annual parallax shift of 5.27 mas,[1] it is located roughly 620 light years from the Sun. This is an evolved red giant star with a stellar classification of M1.5 IIIb.[3] It is currently on the asymptotic giant branch[9] and is a variable star of uncertain type, showing a change in brightness with an amplitude of 0.0147 magnitude and a frequency of 0.02455 cycles per day, or 40.7 days/cycle.[10] On average, it is radiating 932 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,889 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:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Walker, R. L., Jr. (April 1971), "UBV Photometry of 173 PZT Stars", Publications of the Astronomical Society of the Pacific, 83 (492): 177, Bibcode:1971PASP...83..177W, doi:10.1086/129097. 
  3. ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", The Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373. 
  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:1208.3048Freely accessible, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61. 
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  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:1208.2037Freely accessible, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x. 
  7. ^ "mu. 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:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  9. ^ Eggen, O. J. (1992), "Asymptotic giant branch stars near the sun", The Astronomical Journal, 104: 275, Bibcode:1992AJ....104..275E, doi:10.1086/116239. 
  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/0112194Freely accessible, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x.