WR 104
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 02m 04.07s |
| Declination | −23° 37′ 41.2″ |
| Apparent magnitude (V) | 13.28 (12.7 - 14.6) + 15.36 |
| Characteristics | |
| Evolutionary stage | Wolf–Rayet star |
| Spectral type | WC9d/B0.5V + O8V–O5V |
| Astrometry | |
| Proper motion (μ) | RA: 0.161 mas/yr Dec.: −1.827 mas/yr |
| Parallax (π) | 0.2431±0.0988 mas |
| Distance | 2,580±120 pc |
| Absolute magnitude (MV) | −5.4 (−4.8 + −4.6) |
| Orbit | |
| Period (P) | 241.5 days |
| Semi-major axis (a) | 2.34 AU |
| Eccentricity (e) | < 0.06 |
| Inclination (i) | < 16° |
| Details | |
| Mass | 30 M☉ |
| Luminosity | 120,000 L☉ |
| Age | 7 Myr |
| WR | |
| Mass | 10 M☉ |
| Radius | 3.29 R☉ |
| Luminosity | 40,000 L☉ |
| Temperature | 45,000 K |
| OB | |
| Mass | 20 M☉ |
| Radius | 10 R☉ |
| Luminosity | 80,000 L☉ |
| Temperature | 30,000 K |
| B | |
| Radius | 7.98 R☉ |
| Luminosity | 68,000 L☉ |
| Temperature | ≥33,000 K |
| Other designations | |
| V5097 Sgr, IRAS 17590-2337, UCAC2 22296214, CSI−23-17590, IRC −20417, RAFGL 2048, MSX6C G006.4432-00.4858, Ve 2-45 | |
| Database references | |
| SIMBAD | data |
WR 104 is a triple star system located about 2,580 parsecs (8,400 ly) from Earth. The primary star is a Wolf–Rayet star (abbreviated as WR), which has a B0.5 main sequence star in close orbit and another more distant fainter companion.
The WR star is surrounded by a distinctive spiral Wolf–Rayet nebula, often referred to as a pinwheel nebula. The rotational axis of the binary system, and likely of the two closest stars, is directed approximately towards Earth. Within the next few hundred thousand years, the Wolf–Rayet star is predicted to experience a core-collapse supernova with a small chance of producing a long-duration gamma-ray burst.
The possibility of a supernova explosion from WR 104 having destructive consequences for life on Earth stirred interest in the mass media, and several popular science articles have been issued in the press since 2008. Some articles decide to reject the catastrophic scenario, while others leave it as an open question.