WR 136
 WR 136 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 12m 06.5421s |
| Declination | +38° 21′ 17.779″ |
| Apparent magnitude (V) | 7.48 |
| Characteristics | |
| Spectral type | WN6(h) |
| U−B color index | ? |
| B−V color index | 0.009 ± 0.047 |
| Variable type | None |
| Astrometry | |
| Radial velocity (Rv) | −21.6 km/s |
| Proper motion (μ) | RA: −7.54 mas/yr Dec.: −7.38 mas/yr |
| Parallax (π) | 0.61 ± 0.63 mas |
| Distance | approx. 5,000 ly (approx. 2,000 pc) |
| Absolute magnitude (MV) | −4.7[1] |
| Details | |
| Mass | 15[1] M☉ |
| Radius | 3.34[1] R☉ |
| Luminosity | 105.4[1] L☉ |
| Temperature | 70,800[1] K |
| Metallicity | ? |
| Rotation | ? |
| Age | 4.5 million years |
| Other designations | |
| Database references | |
| SIMBAD | data |
WR 136 is a Wolf–Rayet star located in the constellation Cygnus. It is in the center of the Crescent Nebula. Its age is estimated to be around 4.5 million years[2] and it is nearing the end of its life. Within the next few millon years, it is expected to explode as a supernova.[3]
Features
According to recent estimations, WR 136 is 250,000 times brighter than our Sun, 15 times more massive, and 3.3 times larger. Its surface temperature is around 70,000° Kelvin.[1]
WR 136 blew off a shell of material when it became a red supergiant around 250,000 years ago with a mass of around 30 solar masses.[2] Currently, its fast stellar wind, ejected from the star at around 3.8 million mph (6.1 km/h), is catching up to the material ejected from the star and shaping it into a shell. UV rays emitted from WR 136's hot surface cause the shell to glow.[4]
There's certain evidence WR 136 may be a binary star. Its companion would be a low-mass star of spectral classification K or M that would complete an orbit around the Wolf-Rayet star each 5.13 days, being the system the progenitor of a low-mass X-ray binary.[5]
See also
- NGC 6888
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Hamann, W.-R.; Gräfener, G.; Liermann, A. "The Galactic WN stars. Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation". Astronomy and Astrophysics 457 (3). pp. 1015–1013. Bibcode:2006A&A...457.1015H. Retrieved 17 July 2013.
- ↑ 2.0 2.1 "WR 136".
- ↑ "Crescent Nebula Close-up (NGC 6888)".
- ↑ Moore, Brian D.; Hester, Jeff; Scowen, Paul; Dufour, Reginald (13 July 2000). "Hubble Watches Star Tear Apart its Neighborhood". NASA.
- ↑ Rustamov, D. N.; Cherepashchuk, A. M. "The Wolf-Rayet star HD 192163 as a possible evolutionary progenitor of a low-mass X-ray binary". Astronomy Reports 55 (4). pp. 347–358. Bibcode:2011ARep...55..347R. Retrieved 17 July 2013.
- http://www.springerlink.com/content/04205412121836v4/
- http://chandra.harvard.edu/photo/2003/ngc6888/
- http://www.giga-parsec.de/WRspectra.html
- http://www.castfvg.it/stelle/spettri/O/wr_136_01.htm
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