Mu Coronae Borealis

Mu Coronae Borealis, Latinized from μ Coronae Borealis, is a solitary,^[9] ruby-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 5.92 mas, it is located roughly 551 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^[10] 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.^[11] On average, it is radiating 2,512 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,600 K.

μ Coronae Borealis

Location of μ Coronae Borealis (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Corona Borealis
Right ascension	15h 35m 14.91862s[1]
Declination	+39° 00′ 36.2427″[1]
Apparent magnitude (V)	5.12[2]
Characteristics
Spectral type	M1.5 IIIb[3]
U−B color index	+2.01[2]
B−V color index	+1.64[2]
Astrometry
Radial velocity (Rv)	−13.17±0.35[4] km/s
Proper motion (μ)	RA: +24.780[1] mas/yr Dec.: +8.594[1] mas/yr
Parallax (π)	5.9176±0.0830 mas[1]
Distance	551 ± 8 ly (169 ± 2 pc)
Absolute magnitude (MV)	−1.25[5]
Details
Mass	3.0[6] M☉
Radius	78[7] R☉
Luminosity	2,512[6] L☉
Surface gravity (log g)	1.5[7] cgs
Temperature	3,600[6] K
Other designations
μ CrB, 6 CrB, BD+34°2773, HD 139153, HIP 76307, HR 5800[8]
Database references
SIMBAD	data