Beta Coronae Australis
Beta Coronae Australis (Beta CrA), Latinized from β Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.10. The star is located around 470 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of 2.7 km/s. At its current distance, Beta CrA's brightness is diminished by 0.29 magnitudes due to interstellar dust.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 19h 10m 01.75580s |
| Declination | −39° 20′ 26.8644″ |
| Apparent magnitude (V) | 4.10±0.01 |
| Characteristics | |
| Spectral type | K0 II/III CN1.5 |
| U−B color index | +1.07 |
| B−V color index | +1.20 |
| R−I color index | +0.61 |
| Astrometry | |
| Radial velocity (Rv) | 2.7±0.7 km/s |
| Proper motion (μ) | RA: +4.37 mas/yr Dec.: −36.65 mas/yr |
| Parallax (π) | 6.88 ± 0.25 mas |
| Distance | 470 ± 20 ly (145 ± 5 pc) |
| Absolute magnitude (MV) | −1.71 |
| Details | |
| Mass | 5.17±0.26 M☉ |
| Radius | 38.5±1.9 R☉ |
| Luminosity | 614±33 L☉ |
| Surface gravity (log g) | 1.26 cgs |
| Temperature | 4,575±55 K |
| Metallicity [Fe/H] | +0.24 dex |
| Rotational velocity (v sin i) | 6.2±2 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Beta CrA has a stellar classification of K0 II/III CN1.5, indicating that it is an evolved K-type star with the blended luminosity class of a bright giant and a regular giant star. The suffix CN1.5 indicates that the object has an anamolous overabundance of cyano radicals in its spectrum, making it a CN star. Having exhausted the supply of hydrogen at its core, the star has expanded to 39 times the Sun's girth. It has 5.17 times the mass of the Sun shines with a luminosity 614 times that of the Sun from its photosphere at a surface temperature of 4,575 K. Beta CrA is metal enriched (174% solar iron abundance) and spins modestly with a projected rotational velocity of 6.2 km/s.