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Beta Coronae Australis
Star in the constellation Corona Australis / From Wikipedia, the free encyclopedia
Beta Coronae Australis (Beta CrA), Latinized from β Coronae Australis, is a solitary star[15] 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.[2] The star is located around 470 light years distant from the Sun based on parallax,[1] and is drifting further away with a radial velocity of 2.7 km/s.[5] At its current distance, Beta CrA's brightness is diminished by 0.29 magnitudes due to interstellar dust.[16]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Corona Australis |
Right ascension | 19h 10m 01.75580s[1] |
Declination | −39° 20′ 26.8644″[1] |
Apparent magnitude (V) | 4.10±0.01[2] |
Characteristics | |
Spectral type | K0 II/III CN1.5[3] |
U−B color index | +1.07[4] |
B−V color index | +1.20[4] |
R−I color index | +0.61[4] |
Astrometry | |
Radial velocity (Rv) | 2.7±0.7[5] km/s |
Proper motion (μ) | RA: +4.37 mas/yr[1] Dec.: −36.65 mas/yr[1] |
Parallax (π) | 6.88 ± 0.25 mas[1] |
Distance | 470 ± 20 ly (145 ± 5 pc) |
Absolute magnitude (MV) | −1.71[6] |
Details | |
Mass | 5.17±0.26[7] M☉ |
Radius | 38.5±1.9[8] R☉ |
Luminosity | 614±33[9] L☉ |
Surface gravity (log g) | 1.26[10] cgs |
Temperature | 4,575±55[11] K |
Metallicity [Fe/H] | +0.24[10] dex |
Rotational velocity (v sin i) | 6.2±2[12] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Beta CrA has a stellar classification of K0 II/III CN1.5,[3] 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.[9] It has 5.17 times the mass of the Sun shines with a luminosity 614 times that of the Sun[9] from its photosphere at a surface temperature of 4,575 K.[11] Beta CrA is metal enriched (174% solar iron abundance[10]) and spins modestly with a projected rotational velocity of 6.2 km/s.[12]