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Effects of wind clumping on colliding winds

Published online by Cambridge University Press:  07 August 2017

Sébastien Lépine*
Affiliation:
Département de Physique, Université de Montréal, C.P. 6128, Succ. A, Montréal, QC, H3C 3J7, Canada, and Observatoire du Mont-Mégantic

Abstract

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Recent studies of variable Wolf-Rayet emission lines reveal a hierarchy of structures, characterized by power laws analogous to what is expected from supersonic compressible turbulence. The collision of inhomogeneous winds can be very different from the case of smooth winds. The difference will mainly depend on two factors: (i) the relative importance of the inhomogeneous compared to the homogeneous component; and (ii) the characteristic filling factor of the inhomogeneous component. Using relations derived from observations of variable line structures (“blobs”), it can be deduced that the flux emitted by the inhomogeneous part of the wind of a WR star is dominated by its smallest structures. This implies that a significant fraction of the underlying emission line profile could be produced by small, undetectable inhomogeneities. It can also be deduced that the volume spanned by the inhomogeneities is dominated by the largest structures. This in turn implies that the filling factor should be low, or that we are dealing with a fractal-like hierarchy. It is suggested that the wind is composed of dense structures separated by large “voids” which may actually be filled by a homogeneous wind component. The interacting zone of two inhomogeneous colliding winds should thus be much more extended in space than for a smooth-wind model, because the dense, inhomogeneous structures are able to penetrate through the large “voids”.

Type
Session VII - Hydrodynamics and high-energy physics of colliding winds
Copyright
Copyright © Kluwer 1995 

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