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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 448295.0, MPI für Astronomie / Publikationen_mpia
A systematic search for corotating interaction regions in apparently single galactic Wolf-Rayet stars. I. Characterizing the variability
Authors:St-Louis, N.; Chené, A. N.; Schnurr, O.; Nicol, M. H.
Date of Publication (YYYY-MM-DD):2009
Title of Journal:The Astrophysical Journal
Journal Abbrev.:ApJ
Issue / Number:2
Start Page:1951
End Page:1962
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:We present the results of a systematic search for large-scale spectroscopic variability in apparently single Wolf-Rayet (WR) stars brighter than v ~ 12.5. In this first paper we characterize the various forms of variability detected and distinguish several separate groups. For each star in our sample, we obtained 4-5 high-resolution spectra with signal-to-noise ratio ~100. Our ultimate goal is to identify new candidates presenting variability that potentially comes from corotating interaction regions (CIRs). Out of a sample of 25 stars, 10 were found to display large-scale changes of which four are of CIR-type (WR 1, WR 115, WR 120, and WR 134). The star WR 134 was already known to show such changes from previous studies. Three WN8 stars present a different type of large-scale variability and we believe deserve a group of their own. Also, all three WC9d stars in our sample present large-scale variability, but it remains to be checked if these are binaries, as many dust-making WR stars are double. Finally, of the remaining stars, 10 were found to show small-amplitude spectral changes, which we attribute to normal line-profile variability due to inhomogeneities in the wind, and five were found to show no spectral variability, as far as can be concluded from the data in hand. Follow-up studies are required to identify potential periods for our candidates showing CIR-type changes and eventually estimate a rotation rate for these WR stars.
Free Keywords:stars: mass loss; stars: variables: other; stars: winds; outflows; stars: Wolf-Rayet
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/abs/2009ApJ...698.1951S [ID No:1]
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