Epsilon Coronae Australis
Epsilon Coronae Australis (ε CrA), is a star system located in the constellation Corona Australis. Varying in brightness between apparent magnitudes of 4.74 to 5 over 14 hours, it is the brightest W Ursae Majoris variable (low mass contact binary) in the night sky.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 18h 58m 43.37714s |
| Declination | −37° 06′ 26.4865″ |
| Apparent magnitude (V) | +4.75 |
| Characteristics | |
| Spectral type | F4V Fe-0.8 |
| U−B color index | +0.01 |
| B−V color index | +0.39 |
| Variable type | W UMa |
| Astrometry | |
| Radial velocity (Rv) | 57.90 ± 1.2 km/s |
| Proper motion (μ) | RA: −132.40 mas/yr Dec.: −110.62 mas/yr |
| Parallax (π) | 33.13 ± 0.33 mas |
| Distance | 98.4 ± 1.0 ly (30.2 ± 0.3 pc) |
| Absolute magnitude (MV) | 2.21 |
| Orbit | |
| Period (P) | 0.59143357 ± 0.00000016 d |
| Semi-major axis (a) | 3.795 ± 0.052 R☉ |
| Eccentricity (e) | 0 |
| Inclination (i) | 73.05 ± 0.16° |
| Longitude of the node (Ω) | 2.0113 ± 0.0033° |
| Periastron epoch (T) | JD 2442296.95907 ± 0.0070 |
| Details | |
| ε CrA A | |
| Mass | 1.9 M☉ |
| Radius | 2.167 R☉ |
| Temperature | 6481 ± 20 K |
| Rotational velocity (v sin i) | 148.5 km/s |
| ε CrA B | |
| Mass | 0.24 M☉ |
| Radius | 0.869 R☉ |
| Temperature | 5939 ± 19 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
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