Observing massive stars with MOST: the enigmatic WN8 star WR123
- Author(s)
- Laure Lefevre, Sergey V. Marchenko, Anthony F J Moffat, Jaymie M. Matthews, Rainer Kuschnig, David B. Guenther, Slavek M. Rucinski, Dimitar Sasselov, Gordon A. H. Walker, Werner Wolfgang Weiss
- Abstract
We present the results of intensive visual-broadband photometric monitoring of the highly variable WN8 Wolf-Rayet star WR123, obtained by the MOST (Microvariability and Oscillations of STars) satellite, in a way a kind of precursor to COROT to be launched in 2006. This first Canadian astronomical space telescope observed WR123 for 38 days non-stop during June/July 2004. Fourier analysis shows that no periodic signal is stable for more than several days in the low-frequency domain (f <1 d-1), where most of the power is contained. Also, no significant variability is seen at all in the high-frequency domain (10 d-1 <f <1400 d-1) down to the level of 0.2 mmag, an order of magnitude lower than theoretical predictions for strange-mode pulsations. On the other hand, there seems to be a relatively stable 9.8 hr periodic signal present throughout the whole run. This period is probably too short to represent the axial rotation of the star, unless related to multiple sub-structures equidistantly spread along the stellar equator. It is also too short to be orbital in nature; it is more likely to be related to pulsational instabilities (although with a much longer period than expected), thus finally revealing a possible fundamental driver behind the highly variable wind of this object, and others of similar type.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- University of Montreal, Western Kentucky University, University of British Columbia (UBC), Saint Mary's University, University of Toronto, Harvard-Smithsonian Center for Astrophysics
- Pages
- 291
- Publication date
- 2005
- Austrian Fields of Science 2012
- 1030 Physics, Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/cf22cf67-866c-4122-a85c-72910c539874