WR 136

{{short description|Star in the constellation of Cygnus}}

{{Starbox begin

| name=WR 136

}}

{{Starbox image

| image = 250px

| caption = A light curve for V1770 Cygni, plotted from TESS data

}}

{{Starbox observe

| epoch=J2000

| constell=Cygnus{{cite constellation|WR 136}}

| ra={{RA|20|12|06.5421}}{{cite journal|bibcode=2007A&A...474..653V|title=Validation of the new Hipparcos reduction|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653–664|last1=Van Leeuwen|first1=F.|year=2007|doi=10.1051/0004-6361:20078357|arxiv = 0708.1752 |s2cid=18759600}}

| dec={{DEC|+38|21|17.779}}

| appmag_v=7.50{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|pages=0|last1=Ducati|first1=J. R.|year=2002}}

}}

{{Starbox character

| class=WN6(h)-s

| b-v=+0.01

| u-b=−0.37

| variable=

}}

{{Starbox astrometry

| radial_v=−21.6{{cite journal|bibcode=1994A&AS..108..603B|title=Third bibliographic catalogue of stellar radial velocities (Text in French)|journal=Astronomy and Astrophysics Supplement Series |volume=108|pages=603|last1=Barbier-Brossat|first1=M.|last2=Petit|first2=M.|last3=Figon|first3=P.|year=1994}}

| prop_mo_ra=−7.54

| prop_mo_dec=−7.38

| parallax=0.4865

| p_error=0.0337

| parallax_footnote={{cite DR2|2061690233159124352}}

| absmag_v=−5.63

}}

{{Starbox detail

| mass=21{{cite journal|arxiv=1904.04687|last1=Sota|first1=A.|title=The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters|last2=Maíz Apellániz|first2=J.|last3=Morrell|first3=N. I.|last4=Barbá|first4=R. H.|last5=Walborn|first5=N. R.|last6=Gamen|first6=R. C.|last7=Arias|first7=J. I.|last8=Alfaro|first8=E. J.|last9=Oskinova|first9=L. M.|journal=Astronomy & Astrophysics|year=2019|volume=A57|page=625|doi=10.1051/0004-6361/201834850|bibcode=2019A&A...625A..57H|s2cid=104292503}}

| radius=5.10

| luminosity=600,000

| temperature=70,800

| metal=

| rotation=37{{cite journal|doi=10.1051/0004-6361/201118664|title=Rotating Wolf-Rayet stars in a post RSG/LBV phase|journal=Astronomy & Astrophysics|volume=547|pages=A83|year=2012|last1=Gräfener|first1=G.|last2=Vink|first2=J. S.|last3=Harries|first3=T. J.|last4=Langer|first4=N.|bibcode=2012A&A...547A..83G|arxiv = 1210.1153 |s2cid=55530420}}

| age_myr=4.7{{cite journal|doi=10.1086/301389|title=Hubble Space Telescope Observations of the Wolf-Rayet Nebula NGC 6888|journal=The Astronomical Journal|volume=119|issue=6|pages=2991|year=2000|last1=Moore|first1=Brian D.|last2=Hester|first2=J. Jeff|last3=Scowen|first3=Paul A.|bibcode=2000AJ....119.2991M|arxiv = astro-ph/0003053 |s2cid=17769849}}

}}

{{Starbox catalog

| names=V1770 Cyg, AG+38 1977, GSC 03151-01765, BD+37 3821, HD 192163, HIP 99546, GC 28056, SAO 69592.

}}

{{Starbox reference

| Simbad=WR+136

}}

{{Starbox end}}

File:NGC 6888 HOO By Don Christopher Deaver.jpg]]

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 4.7 million years and it is nearing the end of its life. Within a few hundred thousand years, it is expected to explode as a supernova.

According to recent estimations, WR 136 is 600,000 times brighter than the Sun, 21 times more massive, and 5.1 times larger. Its surface temperature is around 70,000 kelvins.

WR 136 blew off a shell of material with a mass of around {{solar mass|5}} when it became a red supergiant around 120,000–240,000 years ago and this is still expanding at 80 km/s.{{cite journal|bibcode=2014ApJ...785..100M|title=The Trace of the CNO Cycle in the Ring Nebula NGC 6888|journal=The Astrophysical Journal|volume=785|issue=2|pages=100|last1=Mesa-Delgado|first1=A.|last2=Esteban|first2=C.|last3=García-Rojas|first3=J.|last4=Reyes-Pérez|first4=J.|last5=Morisset|first5=C.|last6=Bresolin|first6=F.|year=2014|doi=10.1088/0004-637X/785/2/100|arxiv = 1402.6181 |s2cid=118596124}} Currently, its fast stellar wind, ejected from the star at around 3.8 million mph (1,700 km/s{{cite journal|bibcode=1994A&A...281..184H|title=Non-LTE spectral analyses of Wolf-Rayet stars: The nitrogen spectrum of the WN6 prototype HD 192163 (WR136)|journal=Astronomy and Astrophysics |issn=0004-6361|volume=281|pages=184|last1=Hamann|first1=W.-R.|last2=Wessolowski|first2=U.|last3=Koesterke|first3=L.|year=1994}}), is catching up to the material ejected from the star and shaping it into a shell. Ultraviolet rays emitted from WR 136's hot surface cause the shell to glow.

There is some 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 progenitor of a low-mass X-ray binary system.

{{Cite journal|url = http://cdsads.u-strasbg.fr/abs/2011ARep...55..347R

|last1=Rustamov

|first1=D. N.

|last2=Cherepashchuk

|first2=A. M.

|title=The Wolf-Rayet star HD 192163 as a possible evolutionary progenitor of a low-mass X-ray binary

|journal=Astronomy Reports

|volume=55

|issue=4

|pages=347–358

|bibcode=2011ARep...55..347R

|access-date= 17 July 2013

|year=2011

|doi=10.1134/S1063772911010069

|s2cid=121379439

|url-access=subscription

}}