Pulsations and Mass-loss in Massive Wolf - Rayet Stars: M O S T Observations of W R 123 and W R 103
- Autor(en)
- Sergey V. Marchenko, Laure Lefevre, Anthony F J Moffat, B.E. Zhilyaev, André-Nicolas Chene, Jaymie M. Matthews, Rainer Kuschnig, David B. Guenther, Slavek M. Rucinski, Dimitar Sasselov, Gordon A. H. Walker, Werner Wolfgang Weiss
- Abstrakt
The massive, luminous Population I Wolf-Rayet stars drive fast, dense winds.Their sustained (on evolutionary time scales) mass-loss rates exceed theoretical predictions by an order of magnitude. Looking for an alternative mechanism which may help to boost the mass-loss rate, we obtained long-term (5.5 weeks), high-quality, non-stop photometry of two presumably single WR stars, WR 123 (WN8) and WR103 (WC8), using the unique capabilities of the MOST (Microvariability and Oscillations of Stars), a specialized astrophysical micro-satellite. Our targets belong to the cool end of each of the two different evolutionary branches of the WR family: WR123 is ascribed to the WN (Nitrogen-rich) class, while WR103 represents the WC group (Carbon-rich; perceived to be a more advanced evolutionary stage following WN). Despite the difference in evolutionary paths, both stars show dynamic, complex power spectra, with multiple components in the range f (0.1-10) d-1, coherency times not exceeding 10d, and typical amplitudes 5-20 mmag. The photometry provides very strict upper limits on short-term pulsations: amplitudes less than 0.2 mmag for any frequencies higher than 10 d-1. Simultaneous spectroscopy, by probing conditions in the stellar winds, allowed us to link, quite unequivocally, the observed photometric variability to pulsations of the stellar cores.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- Western Kentucky University, Université de Montréal, Universidad de Concepción, National Academy of Sciences of Ukraine (NASU), University of British Columbia (UBC), Saint Mary's University, University of Toronto, Harvard-Smithsonian Center for Astrophysics
- Journal
- Bulletin of the American Astronomical Society
- Band
- 38
- Seiten
- 121
- ISSN
- 0002-7537
- Publikationsdatum
- 2006
- ÖFOS 2012
- 1030 Physik, Astronomie
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/01ab27dc-05dd-4d17-acc9-1e3b37b47482