Epsilon Coronae Australis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Corona Australis |
| Right ascension | 18h 58m 43.37714s |
| Declination | −37° 06′ 26.4865″ |
| Apparent magnitude (V) | 4.83±0.02 |
| 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 (2.39 + 4.98) |
| Orbit | |
| Period (P) | 0.59145447(30) days |
| Semi-major axis (a) | 3.82±0.02 R☉ |
| Eccentricity (e) | 0 |
| Inclination (i) | 74.02±0.14° |
| Longitude of the node (Ω) | 2.0113 ± 0.0033° |
| Periastron epoch (T) | HJD 3966.6892(0.0696) |
| Semi-amplitude (K1) (primary) | 36.40±0.05 km/s |
| Semi-amplitude (K2) (secondary) | 273.70±0.05 km/s |
| Details | |
| ε CrA A | |
| Mass | 1.89±0.16 M☉ |
| Radius | 2.14±0.09 R☉ |
| Luminosity | 8.9±1.8 L☉ |
| Temperature | 6,820±200 K |
| Rotational velocity (v sin i) | 148.5 km/s |
| Age | 2.83±0.28 Gyr |
| ε CrA B | |
| Mass | 0.25±0.04 M☉ |
| Radius | 0.84±0.04 R☉ |
| Luminosity | 0.85±0.14 L☉ |
| Surface gravity (log g) | 3.99±0.03 cgs |
| Temperature | 6,050±100 K |
| Age | 2.83±0.28 Gyr |
| Other designations | |
| ε CrA, CD−37°13001, CPD−37°8433, HD 175813, HIP 93174, HR 7152, SAO 210781 | |
| Database references | |
| SIMBAD | data |
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.