ORBi: Rauw Grégor - WR22: the most massive Wolf-Rayet star ever weighed.

Reference : WR22: the most massive Wolf-Rayet star ever weighed.


	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
	To cite this reference:	http://hdl.handle.net/2268/15911

Title :	WR22: the most massive Wolf-Rayet star ever weighed.
Language :	English
Author, co-author :	Rauw, Grégor [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE) - Sciences spatiales >]
	Vreux, Jean-Marie [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > > ]
	Gosset, Eric [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Groupe d'astrophysique des hautes énergies (GAPHE) >]
	Hutsemekers, Damien [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
	Magain, Pierre [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
	Rochowicz, K. [> > > >]
Publication date :	1-Feb-1996
Journal title :	Astronomy and Astrophysics
Publisher :	EDP Sciences
Volume :	306
Pages :	771-782
Audience :	International
ISSN :	0004-6361
e-ISSN :	1432-0746
City :	Les Ulis
Country :	France
Keywords :	[en] STARS: INDIVIDUAL: WR22 ; STARS: WOLF-RAYET ; BINARIES: SPECTROSCOPIC ; BINARIES: ECLIPSING ; STARS: FUNDAMENTAL PARAMETERS
Abstract :	[en] The results of an extensive spectroscopic campaign on the eclipsing binary WR22 are presented. A new radial velocity curve is deduced for the WN7 component, allowing us to improve the parameters of the orbit, formerly determined on the basis of photographic spectra. The high signal-to-noise ratio of our data also allows the detection of some weak absorption lines which, for the first time, can definitely be attributed to the companion. A study of their radial velocities gives a mass ratio of m_WR_/m_O_=2.78 leading to a minimum mass of 72M[SUB]sun[/SUB]_ for the WN7 star. The companion can be classified as a "late O" (O6.5-O8.5) star with a luminosity ratio of the system q=L_WR_^y^/L_O_^y^ at 5500A of about 8. The exceptionally high mass of the WN7 star and its high hydrogen mass-fraction suggest that WR22 is at the beginning of its Wolf-Rayet evolution. As a matter of fact, with such a high mass, WR22 most probably is still a hydrogen burning object. Therefore, the WN7 component is much closer to a main sequence O star with a "Wolf-Rayet clothing" than to the other members of the Wolf-Rayet family, which are rather highly evolved He-burning descendants of massive progenitors.
Permalink :	http://hdl.handle.net/2268/15911
Other URL :	http://adsabs.harvard.edu/abs/1996A%26A...306..771R

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