WR 148 shows a classic WN8h spectrum, but with the addition of weak central absorption on some of the emission lines.[11] NIII and NIV emission lines are stronger than NV, and HeI lines are stronger than HeII, The Balmer series hydrogen lines and some other lines have P Cygni profiles.[12]
WR 148 is erratically variable on timescales ranging from seconds to years, but it shows consistent brightness and radial velocity variations with a period of 4.32 days. There is little doubt that it is a binary system, due to the regular variations and the presence of hard x-ray radiation from colliding winds, but the secondary is not clearly detectable in the spectrum.[4] One proposal for a companion that would match the faint absorption features would be a B3 subgiant, but that is not compatible with the orbit. An early calculated orbit based on faint absorption features gave a relatively large mass ratio which imply either a very high companion mass, meaning a black hole, or an unreasonably low primary mass for a luminous WR star.[11] Another analysis of the spectrum finds absorption features consistent with an O5 star, similar masses for the two components, and only a small orbital inclination.[4]
Because of its erratic changes in apparent magnitude at so many frequencies WR 148 is classified in the General Catalogue of Variable Stars as a unique type of variable, not a member of any of the defined classes.[3] The shape of the light curve is unusual and has been modelled as being produced by an extended secondary object which may be an ionised cavity in the dense wind of the primary star, produced as the secondary orbits at a distance comparable to the radius of the primary star.[11]
WR 148 is found unusually far from the galactic plane for a Wolf–Rayet star, at 500–800 pc. Young massive stars such as WN8h WR stars are members of the thin disc population, on average only 60 pc from the galactic plane. It is suggested that WR 148 is a runaway from a supernova explosion.[11] Calculations based on its large peculiar velocity of 197 km/s, current binary orbit, and likely lifetime since any supernova, are consistent with expulsion from a very massive triple system.[4]
Referencesedit
^"OMC Archive". OMC Archive. The Astronomical Data Centre at CAB. Retrieved 19 December 2021.
^ abcdeVallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
^ abcSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
^ abcdefghiMunoz, Melissa; Moffat, Anthony F. J.; Hill, Grant M.; Shenar, Tomer; Richardson, Noel D.; Pablo, Herbert; St-Louis, Nicole; Ramiaramanantsoa, Tahina (2017). "WR 148: Identifying the companion of an extreme runaway massive binary*". Monthly Notices of the Royal Astronomical Society. 467 (3): 3105. arXiv:1609.08289. Bibcode:2017MNRAS.467.3105M. doi:10.1093/mnras/stw2283. S2CID 119199391.
^Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
^Van Der Hucht, K. A. (2006). "New Galactic Wolf–Rayet stars, and candidates. An annex to the VIIth Catalogue of Galactic Wolf–Rayet Stars". Astronomy and Astrophysics. 458 (2): 453–459. arXiv:astro-ph/0609008. Bibcode:2006A&A...458..453V. doi:10.1051/0004-6361:20065819. S2CID 119104786.
^ abDucati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
^Zhekov, Svetozar A. (2012). "X-rays from colliding stellar winds: The case of close Wolf–Rayet+O binary systems". Monthly Notices of the Royal Astronomical Society. 422 (2): 1332–1342. arXiv:1202.1386. Bibcode:2012MNRAS.422.1332Z. doi:10.1111/j.1365-2966.2012.20706.x. S2CID 86867278.
^ abcdHamann, W.-R.; Gräfener, G.; Liermann, A. (2006). "The Galactic WN stars. Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation". Astronomy and Astrophysics. 457 (3): 1015. arXiv:astro-ph/0608078. Bibcode:2006A&A...457.1015H. doi:10.1051/0004-6361:20065052. S2CID 18714731.
^Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J.; Oskinova, L. M. (2019). "The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters". Astronomy & Astrophysics. A57: 625. arXiv:1904.04687. Bibcode:2019A&A...625A..57H. doi:10.1051/0004-6361/201834850. S2CID 104292503.
^ abcdMarchenko, Sergey V.; Moffat, Anthony F. J.; Lamontagne, Robert; Tovmassian, Gaghik H. (1996). "The Wolf–Rayet Star HD 197406, with Its Strongly Ionizing Close Companion". Astrophysical Journal. 461: 386. Bibcode:1996ApJ...461..386M. doi:10.1086/177067.
^Smith, Lindsey F.; Shara, Michael M.; Moffat, Anthony F. J. (1996). "A three-dimensional classification for WN stars". Monthly Notices of the Royal Astronomical Society. 281 (1): 163–191. Bibcode:1996MNRAS.281..163S. doi:10.1093/mnras/281.1.163.
January 01, 1970
spectroscopic, binary, constellation, cygnus, primary, star, wolf, rayet, star, most, luminous, stars, known, secondary, been, suspected, being, stellar, mass, black, hole, class, main, sequence, star, visual, band, light, curve, v1696, cygni, plotted, from, i. WR 148 is a spectroscopic binary in the constellation Cygnus The primary star is a Wolf Rayet star and one of the most luminous stars known The secondary has been suspected of being a stellar mass black hole but may be a class O main sequence star WR 148A visual band light curve For V1696 Cygni plotted from INTEGRAL Optical Monitoring Camera OMC data 1 Observation dataEpoch J2000 0 Equinox J2000 0 Constellation Cygnus Right ascension 20h 41m 21 54855s 2 Declination 52 35 15 1426 2 Apparent magnitude V 10 3 3 Characteristics Spectral type WN8h O5V 4 Apparent magnitude J 8 759 5 Apparent magnitude K 8 318 6 U B color index 0 45 7 B V color index 0 57 7 Variable type Unique 3 AstrometryRadial velocity Rv 131 4 2 7 4 km sProper motion m RA 5 629 2 mas yr Dec 3 315 2 mas yrParallax p 0 1022 0 0114 mas 2 Distance8 280 8 pcAbsolute magnitude MV 7 22 9 Orbit 4 Period P 4 317336 daysSemi major axis a 46 R Eccentricity e 0Inclination i 18 Semi amplitude K1 primary 88 1 3 8 km sSemi amplitude K2 secondary 79 2 3 1 km s DetailsWRMass44 10 M Radius26 5 9 R Luminosity1 585 000 9 L Temperature39 800 9 KRotational velocity v sin i 150 4 km sOBMass37 4 M Rotational velocity v sin i 60 20 10 4 km s Other designationsV1696 Cygni BD 52 2777 HD 197406 HIP 102088 Database referencesSIMBADdata WR 148 shows a classic WN8h spectrum but with the addition of weak central absorption on some of the emission lines 11 NIII and NIV emission lines are stronger than NV and HeI lines are stronger than HeII The Balmer series hydrogen lines and some other lines have P Cygni profiles 12 WR 148 is erratically variable on timescales ranging from seconds to years but it shows consistent brightness and radial velocity variations with a period of 4 32 days There is little doubt that it is a binary system due to the regular variations and the presence of hard x ray radiation from colliding winds but the secondary is not clearly detectable in the spectrum 4 One proposal for a companion that would match the faint absorption features would be a B3 subgiant but that is not compatible with the orbit An early calculated orbit based on faint absorption features gave a relatively large mass ratio which imply either a very high companion mass meaning a black hole or an unreasonably low primary mass for a luminous WR star 11 Another analysis of the spectrum finds absorption features consistent with an O5 star similar masses for the two components and only a small orbital inclination 4 Because of its erratic changes in apparent magnitude at so many frequencies WR 148 is classified in the General Catalogue of Variable Stars as a unique type of variable not a member of any of the defined classes 3 The shape of the light curve is unusual and has been modelled as being produced by an extended secondary object which may be an ionised cavity in the dense wind of the primary star produced as the secondary orbits at a distance comparable to the radius of the primary star 11 WR 148 is found unusually far from the galactic plane for a Wolf Rayet star at 500 800 pc Young massive stars such as WN8h WR stars are members of the thin disc population on average only 60 pc from the galactic plane It is suggested that WR 148 is a runaway from a supernova explosion 11 Calculations based on its large peculiar velocity of 197 km s current binary orbit and likely lifetime since any supernova are consistent with expulsion from a very massive triple system 4 References edit OMC Archive OMC Archive The Astronomical Data Centre at CAB Retrieved 19 December 2021 a b c d e Vallenari A et al Gaia collaboration 2023 Gaia Data Release 3 Summary of the content and survey properties Astronomy and Astrophysics 674 A1 arXiv 2208 00211 Bibcode 2023A amp A 674A 1G doi 10 1051 0004 6361 202243940 S2CID 244398875 Gaia DR3 record for this source at VizieR a b c Samus N N Durlevich O V et al 2009 VizieR Online Data Catalog General Catalogue of Variable Stars Samus 2007 2013 VizieR On line Data Catalog B GCVS Originally Published in 2009yCat 102025S 1 Bibcode 2009yCat 102025S a b c d e f g h i Munoz Melissa Moffat Anthony F J Hill Grant M Shenar Tomer Richardson Noel D Pablo Herbert St Louis Nicole Ramiaramanantsoa Tahina 2017 WR 148 Identifying the companion of an extreme runaway massive binary Monthly Notices of the Royal Astronomical Society 467 3 3105 arXiv 1609 08289 Bibcode 2017MNRAS 467 3105M doi 10 1093 mnras stw2283 S2CID 119199391 Cutri Roc M Skrutskie Michael F Van Dyk Schuyler D Beichman Charles A Carpenter John M Chester Thomas Cambresy Laurent Evans Tracey E Fowler John W Gizis John E Howard Elizabeth V Huchra John P Jarrett Thomas H Kopan Eugene L Kirkpatrick J Davy Light Robert M Marsh Kenneth A McCallon Howard L Schneider Stephen E Stiening Rae Sykes Matthew J Weinberg Martin D Wheaton William A Wheelock Sherry L Zacarias N 2003 VizieR Online Data Catalog 2MASS All Sky Catalog of Point Sources Cutri 2003 CDS ADC Collection of Electronic Catalogues 2246 II 246 Bibcode 2003yCat 2246 0C Van Der Hucht K A 2006 New Galactic Wolf Rayet stars and candidates An annex to the VIIth Catalogue of Galactic Wolf Rayet Stars Astronomy and Astrophysics 458 2 453 459 arXiv astro ph 0609008 Bibcode 2006A amp A 458 453V doi 10 1051 0004 6361 20065819 S2CID 119104786 a b Ducati J R 2002 VizieR Online Data Catalog Catalogue of Stellar Photometry in Johnson s 11 color system CDS ADC Collection of Electronic Catalogues 2237 Bibcode 2002yCat 2237 0D Zhekov Svetozar A 2012 X rays from colliding stellar winds The case of close Wolf Rayet O binary systems Monthly Notices of the Royal Astronomical Society 422 2 1332 1342 arXiv 1202 1386 Bibcode 2012MNRAS 422 1332Z doi 10 1111 j 1365 2966 2012 20706 x S2CID 86867278 a b c d Hamann W R Grafener G Liermann A 2006 The Galactic WN stars Spectral analyses with line blanketed model atmospheres versus stellar evolution models with and without rotation Astronomy and Astrophysics 457 3 1015 arXiv astro ph 0608078 Bibcode 2006A amp A 457 1015H doi 10 1051 0004 6361 20065052 S2CID 18714731 Sota A Maiz Apellaniz J Morrell N I Barba R H Walborn N R Gamen R C Arias J I Alfaro E J Oskinova L M 2019 The Galactic WN stars revisited Impact of Gaia distances on fundamental stellar parameters Astronomy amp Astrophysics A57 625 arXiv 1904 04687 Bibcode 2019A amp A 625A 57H doi 10 1051 0004 6361 201834850 S2CID 104292503 a b c d Marchenko Sergey V Moffat Anthony F J Lamontagne Robert Tovmassian Gaghik H 1996 The Wolf Rayet Star HD 197406 with Its Strongly Ionizing Close Companion Astrophysical Journal 461 386 Bibcode 1996ApJ 461 386M doi 10 1086 177067 Smith Lindsey F Shara Michael M Moffat Anthony F J 1996 A three dimensional classification for WN stars Monthly Notices of the Royal Astronomical Society 281 1 163 191 Bibcode 1996MNRAS 281 163S doi 10 1093 mnras 281 1 163 Retrieved from https en wikipedia org w index php title WR 148 amp oldid 1170017859, wikipedia, wiki, book, books, library,
