Mu Coronae Borealis, Latinized from μ Coronae Borealis, is a solitary,[8] 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 5.27 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]
| 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] |
| 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: +24.45[1] mas/yr Dec.: +9.22[1] mas/yr |
| Parallax (π) | 5.27 ± 0.24 mas[1] |
| Distance | 620 ± 30 ly (190 ± 9 pc) |
| Absolute magnitude (MV) | −1.25[5] |
| Details | |
| Luminosity | 932[6] L☉ |
| Temperature | 3,889[6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |