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Inhomogeneous winds: the nature of emission-line profile variations in Wolf-Rayet spectra

Published online by Cambridge University Press:  25 May 2016

Sébastien Lépine*
Affiliation:
Département de Physique, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, ESC 3J7 Canada and Observatoire du Mont-Mégantic
Anthony F.J. Moffat
Affiliation:
Département de Physique, Université de Montréal C.P. 6128, Succ. Centre-Ville, Montréal, ESC 3J7 Canada and Observatoire du Mont-Mégantic
*
1Present address: Research Programs Office, Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, USA

Abstract

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We present the results of simulations which show that stochastic line-profile variations (LPVS) of Wolf-Rayet emission lines can be reproduced with an inhomogeneous wind model, in which line-emission arises from a large number of discrete wind emission elements (DWEES). A comparison between simulations and LPVS from 9 WR stars provides useful information about the nature of the inhomogeneous and dynamical structure of the wind. Although the detailed spatial/fractal structure of the inhomogeneous wind is poorly constrained by analysis of LPVS, simulations suggest the wind to be highly fragmented, being composed of at least 104 DWEES in the line-emission region. Analysis of lpv patterns reaveal DWEES to be associated with large fluctuations in the velocity field. These fluctuations are locally anisotropic; the velocity dispersions of DWEES. are systematically larger in the radial direction (≈vr ≍ 200 km s−1) than in the transverse direction (σvθ ≈ 50 kms−1). lpv patterns also yield estimates of the wind acceleration, which can be used to test hypotheses about the wind velocity-law.

Type
Part 2. Models for single star evolution of massive stars: wind + atmosphere + interior
Copyright
Copyright © Astronomical Society of the Pacific 1999 

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