WR 102
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Sagittarius |
| Right ascension | 17h 45m 47.5s[1] |
| Declination | −26° 10′ 27″[1] |
| Apparent magnitude (V) | 14.10[2] |
| Characteristics | |
| Evolutionary stage | Wolf-Rayet star |
| Spectral type | WO2[3] |
| B−V color index | +0.77[4] |
| Astrometry | |
| Distance | 5,560[5] pc |
| Absolute magnitude (MV) | −1.71[2] |
| Details | |
| Mass | 19[2] M☉ |
| Radius | 0.39[3] R☉ |
| Luminosity | 282,000[3] L☉ |
| Temperature | 210,000[3] K |
| Metallicity [Fe/H] | 0.0[3] dex |
| Rotational velocity (v sin i) | 1,000[2] km/s |
| Other designations | |
|
V3893 Sagittarii, LS 4368, ALS 4368, Sand 4
|
|
| Database references | |
| SIMBAD | data |
WR 102 is a Wolf-Rayet star in the constellation Cygnus, an extremely rare star on the WO oxygen sequence.
Features
WR 102, of spectral classification WO2, is one of the very few known oxygen-sequence Wolf-Rayet stars, just four in the Milky Way galaxy and five in external galaxies. It is also the hottest known with a surface temperature of 210,000 K. Modelling the atmosphere gives a luminosity around 282,000 L☉,[3] while calculations from brightness and distance gives luminosity of nearly 500,000 L☉ although the distance is not known with any certainty.[2] It is a very small dense star, with a radius less than 0.4 solar radii but with a mass nearly 20 solar masses. Very strong stellar winds, with a terminal velocity of 5,000 kilometers per second are causing WR 102 to lose 10−5 M☉/year.[2] For comparison, the Sun loses (2-3) x 10−14 solar masses per year due to its solar wind, several hundred million times less than WR 102.
Evolutionary status
WO Wolf-Rayet stars are the last evolutionary stage of the most massive stars before exploding as supernovae, possibly with a gamma-ray burst.[6] It is very likely that WR 102 is on its last stages of nuclear fusion, near or beyond the end of helium burning.[7] It has been calculated that WR 102 will explode as a supernova within 1,500 years. The mass and rapid rotation make a GRB likely.[3]
See also
References
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