AB7
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Tucana |
| Right ascension | 01h 03m 35.93s |
| Declination | −72° 03′ 22.0″ |
| Apparent magnitude (V) | 13.016 |
| Characteristics | |
| Spectral type | WN4 + O6I(f) |
| U−B color index | −1.021 |
| B−V color index | −0.062 |
| Astrometry | |
| Radial velocity (Rv) | 172 km/s |
| Distance | 197,000 ly (61,000 pc) |
| Absolute magnitude (MV) | −6.1 (−4.4 + −5.7) |
| Orbit | |
| Period (P) | 19.560±0.0005 d |
| Eccentricity (e) | 0.07±0.02 |
| Inclination (i) | 68+22 −15° |
| Periastron epoch (T) | 2,451,549.2±0.8 |
| Argument of periastron (ω) (primary) | 101±16° |
| Semi-amplitude (K1) (primary) | 196±4 km/s |
| Semi-amplitude (K2) (secondary) | 101±2 km/s |
| Details | |
| WR | |
| Mass | 23 M☉ |
| Radius | 3.4 R☉ |
| Luminosity | 1,259,000 L☉ |
| Surface gravity (log g) | 4.7 cgs |
| Temperature | 105,000 K |
| O | |
| Mass | 44 M☉ |
| Radius | 14 R☉ |
| Luminosity | 316,000 L☉ |
| Surface gravity (log g) | 3.6 cgs |
| Temperature | 36,000 K |
| Rotational velocity (v sin i) | 150 km/s |
| Age | 3.4 Myr |
| Other designations | |
| AB 7, SMC WR 7, OGLE SMC-SC9 37124, SBC9 2395, AzV 336a | |
| Database references | |
| SIMBAD | data |
AB7, also known as SMC WR7, is a binary star in the Small Magellanic Cloud. A Wolf–Rayet star and a supergiant companion of spectral type O orbit in a period of 19.56 days. The system is surrounded by a ring-shaped nebula known as a bubble nebula.