 AB7 is the brightest white star at the centre of the cavity within the nebula, not the brighter reddish star.[1] False colour image: red is HI; green is OIII; blue is HeIII. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Tucana |
| Right ascension | 01h 03m 35.93s[2] |
| Declination | −72° 03′ 22.0″[2] |
| Apparent magnitude (V) | 13.016[2] |
| Characteristics | |
| Spectral type | WN4 + O6I(f)[2] |
| U−B color index | −1.021[2] |
| B−V color index | −0.062[2] |
| Astrometry | |
| Radial velocity (Rv) | 172[3] km/s |
| Distance | 197,000 ly (61,000 pc) |
| Absolute magnitude (MV) | −6.1[3] (−4.4 + −5.7[4]) |
| Orbit[3] | |
| Period (P) | 19.560±0.0005 d |
| Eccentricity (e) | 0.07±0.02 |
| Inclination (i) | 68+22 −15[4]° |
| 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[4] | |
| 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 | |
| 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.
- ^ Naze, Y.; Rauw, G.; Manfroid, J.; Chu, Y.-H.; Vreux, J.-M. (September 2003). "WR bubbles and HeII emission". Astronomy & Astrophysics. 408 (1): 171–186. arXiv:astro-ph/0306084. Bibcode:2003A&A...408..171N. doi:10.1051/0004-6361:20030847. S2CID 1612072.
- ^ a b c d e f Bonanos, A. Z.; Lennon, D. J.; Köhlinger, F.; Van Loon, J. Th.; Massa, D. L.; Sewilo, M.; Evans, C. J.; Panagia, N.; Babler, B. L.; Block, M.; Bracker, S.; Engelbracht, C. W.; Gordon, K. D.; Hora, J. L.; Indebetouw, R.; Meade, M. R.; Meixner, M.; Misselt, K. A.; Robitaille, T. P.; Shiao, B.; Whitney, B. A. (2010). "Spitzer SAGE-SMC Infrared Photometry of Massive Stars in the Small Magellanic Cloud". The Astronomical Journal. 140 (2): 416–429. arXiv:1004.0949. Bibcode:2010AJ....140..416B. doi:10.1088/0004-6256/140/2/416. S2CID 119290443.
- ^ a b c Niemela, V. S.; Massey, P.; Testor, G.; Gimenez Benitez, S. (2002). "The massive Wolf-Rayet binary SMC WR7". Monthly Notices of the Royal Astronomical Society. 333 (2): 347–352. arXiv:astro-ph/0202203. Bibcode:2002MNRAS.333..347N. doi:10.1046/j.1365-8711.2002.05395.x. S2CID 15360882.
- ^ a b c Shenar, T.; Hainich, R.; Todt, H.; Sander, A.; Hamann, W.-R.; Moffat, A. F. J.; Eldridge, J. J.; Pablo, H.; Oskinova, L. M.; Richardson, N. D. (2016). "Wolf-Rayet stars in the Small Magellanic Cloud: II. Analysis of the binaries". Astronomy & Astrophysics. 1604: A22. arXiv:1604.01022. Bibcode:2016A&A...591A..22S. doi:10.1051/0004-6361/201527916. S2CID 119255408.