OPTICAL SPECTROSCOPY OF INHOMOGENEITIES IN THE WINDS OF WOLF-RAYET STARS

Recent high quality spectra in the wavelength range 5300-6000 Angstrom of 9 WR stars of different subtypes are presented to study the intrin sic variability of the WR winds. These data clearly show variable subp eaks superimposed on the emission lines of all stars. The global level of variability of the lines decreases while more subpeaks are seen fo r stars with taster winds. The spectroscopic variations are associated to the presence of perturbations in the stellar winds. An inhomogenei ty model is developed to study the dynamic and the physical characteri stics of the wind perturbations. In the case of HD193793, for which mo re structures have been detected, a comparison with the general veloci ty law gives beta > 3. The internal velocity dispersion is larger in t he direction of propagation than perpendicular to it. A histogram of t he flux of the inhomogeneities indicates it larger number of wind stru ctures with small flux. A power law fitted to the flux histogram of ea ch stars gives an average exponent which is compatible with the one se en for giant molecular clouds where supersonic turbulence prevails. Th e physical representation of the WR winds and the origin of the pertur bations is questioned.