Epoch J2000 Equinox J2000
|Right ascension||20h 12m 06.5421s|
|Declination||+38° 21′ 17.779″|
|Apparent magnitude (V)||7.48|
|U−B color index||?|
|B−V color index||0.009 ± 0.047|
|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|
|Age||4.5 million years|
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 and it is nearing the end of its life. Within the next few million years, it is expected to explode as a supernova.
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. Currently, its fast stellar wind, ejected from the star at around 3.8 million mph (6.1 million 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.
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.
- 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.
- "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.
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