Article (Scientific journals)
An investigation of the large-scale variability of the apparently single Wolf-Rayet star WR 1
Morel, Thierry; Georgiev, L. N.; Grosdidier, Y. et al.
1999In Astronomy and Astrophysics, 349, p. 457-466
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Keywords :
STARS: INDIVIDUAL: WR 1; STARS: MASS-LOSS; STARS: WOLF-RAYET
Abstract :
[en] In recent years, much studies have focused on determining the origin of the large-scale line-profile and/or photometric patterns of variability displayed by some apparently single Wolf-Rayet stars, with the existence of an unseen (collapsed?) companion or of spatially extended wind structures as potential candidates. We present observations of <ASTROBJ>WR 1</ASTROBJ> which highlight the unusual character of the variations in this object. Our narrowband photometric observations reveal a gradual increase of the stellar continuum flux amounting to Delta v ~ 0.09 mag followed by a decline on about the same timescale (3-4 days). Only marginal evidence for variability is found during the 11 following nights. Strong, daily line-profile variations are also observed but they cannot be easily linked to the photometric variations. Similarly to the continuum flux variations, coherent time-dependent changes are observed in 1996 in the centroid, equivalent width, and skewness of He Ii lambda 4686. Despite the generally coherent nature of the variations, we do not find evidence in our data for the periods claimed in previous studies. While the issue of a cyclical pattern of variability in <ASTROBJ>WR 1</ASTROBJ> is still controversial, it is clear that this object might constitute in the future a cornerstone for our understanding of the mechanisms leading to the formation of largely anisotropic outflows in Wolf-Rayet stars.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Morel, Thierry  ;  Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada
Georgiev, L. N.;  Instituto de Astronomía, UNAM, Apdo. Postal 70-264, México D.F. 04510, México ()
Grosdidier, Y.;  Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada and Observatoire du Mont Mégantic (morel, yves, stlouis,) ; Observatoire Astronomique de Strasbourg, UMR 7550, 11 rue de l'Université, F-67000 Strasbourg, France
St-Louis, N.;  Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada and Observatoire du Mont Mégantic (morel, yves, stlouis,)
Eversberg, T.;  Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec, H3C 3J7, Canada and Observatoire du Mont Mégantic (morel, yves, stlouis,)
Hill, G. M.;  McDonald Observatory, HET, P.O. Box 1337, Fort Davis, TX, USA ()
Language :
English
Title :
An investigation of the large-scale variability of the apparently single Wolf-Rayet star WR 1
Publication date :
01 September 1999
Journal title :
Astronomy and Astrophysics
ISSN :
0004-6361
eISSN :
1432-0746
Publisher :
EDP Sciences, Les Ulis, France
Volume :
349
Pages :
457-466
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 19 February 2010

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