Modelling the spectra of colliding winds in the Wolf–Rayet WC7+O binaries WR 42 and WR 79 |
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| Authors: | G M Hill A F J Moffat † N St-Louis P Bartzakos |
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| Institution: | Department de Physique and Observatoire du Mont Mégantic, C.P. 6128, Succ. A, Universitéde Montréal, Montréal, PQ H3C 3J7, Canada;Dominion Astrophysical Observatory, National Research Council, 5071 West Saanich Road, Victoria, BC V8X 4M6, Canada;McDonald Observatory, University of Texas at Austin, PO Box 1337, Fort Davis, TX 79734, USA |
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| Abstract: | We have obtained complete phase coverage of the WC7+O binaries WR 42 = HD 97152 and WR 79 = HD 152270 with high signal-to-noise ratio (S/N), moderate-resolution spectra. Remarkable orbital phase-locked profile variations of the C iii λ 5696 line are observed and interpreted as arising from colliding wind effects. Within this scenario, we have modelled the spectra using a purely geometrical model that assumes a cone-shaped wind–wind interaction region which partially wraps around the O star. Such modelling holds the exciting promise of revealing a number of interesting parameters for WR+O binaries, such as the orbital inclination, the streaming velocity of material in the interaction region and the ratio of wind momentum flux. Knowledge of these parameters in turn leads to the possibility of a better understanding of WR star masses, mass-loss rates and wind region characteristics. |
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| Keywords: | binaries: close stars: individual: WR 42 stars: individual: WR 79 stars: mass-loss stars: Wolf–Rayet |
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