T Coronae Borealis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Corona Borealis |
| Right ascension | 15h 59m 30.1622s |
| Declination | +25° 55′ 12.613″ |
| Apparent magnitude (V) | 2.0–10.8 |
| Characteristics | |
| Evolutionary stage | Red giant + white dwarf |
| Spectral type | M3III+p |
| Variable type | recurrent nova |
| Astrometry | |
| Radial velocity (Rv) | −27.75±0.04 km/s |
| Proper motion (μ) | RA: −4.461 mas/yr Dec.: 12.016 mas/yr |
| Parallax (π) | 1.0920±0.0275 mas |
| Distance | 2,990 ± 80 ly (920 ± 20 pc) |
| Absolute magnitude (MV) | +0.16 (min.) |
| Orbit | |
| Period (P) | 227.5528±0.0002 days |
| Semi-major axis (a) | 0.960 AU |
| Eccentricity (e) | 0.009±0.003 |
| Inclination (i) | 61.5° |
| Periastron epoch (T) | 2459978.37±0.08 |
| Semi-amplitude (K1) (primary) | 23.90±0.05 km/s |
| Details | |
| Red giant | |
| Mass | 0.93 M☉ |
| Radius | 63.5±0.3 – 71.1 R☉ |
| Luminosity | 583±4 L☉ |
| Surface gravity (log g) | 0.672+0.009 −0.007 cgs |
| Temperature | 3,561±3 K |
| Metallicity [Fe/H] | +0.20+0.05 −0.03 dex |
| Rotational velocity (v sin i) | 4.75±0.26 km/s |
| White dwarf | |
| Mass | 1.35 M☉ |
| Radius | 0.0045 R☉ |
| Luminosity | ~100 L☉ |
| Other designations | |
| Blaze Star, T CrB, AAVSO 1555+26, BD+26°2765, HD 143454, HIP 78322, HR 5958, SAO 84129, 2MASS J15593015+2555126 | |
| Database references | |
| SIMBAD | data |
T Coronae Borealis is a binary star and a recurrent nova about 3,000 light-years (920 parsecs) away in the constellation Corona Borealis. It has the official proper name Blaze Star, T Coronae Borealis is the variable-star designation. The system was first observed in outburst in 1866 by John Birmingham, though it had been observed earlier in quiescence as a 10th magnitude star. It may have been observed in 1217 and in 1787 as well. In February 1946, Michael Woodman, a 15-year-old schoolboy from Wales, observed a flare‐up, subsequently writing to the Astronomer Royal and leading to the theory that the star flares every 80 years, with the next nova expected to occur before 2027.