| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 18h 47m 32.30962s [2] |
| Declination | −38° 09′ 32.3079″ [2] |
| Apparent magnitude (V) | 9.4 - 17.9 [3] |
| Characteristics | |
| Evolutionary stage | R CrB [3] |
| Spectral type | R0 [4] |
| Astrometry | |
| Proper motion (μ) | RA: −1.104 [2] mas/yr Dec.: −7.531 [2] mas/yr |
| Parallax (π) | −0.3793 ± 0.1513 mas [2] |
| Distance | 5,500 [5] pc |
| Details | |
| Mass | 0.6 [6] M☉ |
| Luminosity | 6,550 [5] L☉ |
| Surface gravity (log g) | 0.5 [7] cgs |
| Temperature | 6,250 [6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
V Coronae Australis (V CrA) is a R Coronae Borealis variable (RCB) star in the constellation Corona Australis. These are extremely hydrogen-deficient supergiants thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. [9] V Coronae Australis dimmed in brightness from 1994 to 1998. [10]
In 1896 it was announced that Evelyn Leland and Williamina Fleming had discovered that the star is a variable star. [11] The visual apparent magnitude of V CrA has been observed to vary between magnitudes 9.4 and 17.9. A maximum magnitude of 8.3 has been estimated from photographic plates. [12] It has around 60% the mass of the Sun and an effective (surface) temperature of around 6250 K. [6]
The spectral class of R0 is typical of a carbon star, but the RCB stars are considered to a separate class of hydrogen-deficient stars, not normal asymptotic giant branch giants. [13]
