A high precision photometric investigation of the micro-variations ofWolf-Rayet stars.

VBLUW photometric observations of seven WR stars, obtained with standard deviation less than about 0.002 mag using the 90-cm Dutch telescope at ESO during March-April 1986, are reported. The observation and data-reduction techniques are discussed, and the results are presented in extensive tables and graphs and characterized in detail. Some of the light and color variations are tentatively attributed to temperature-induced changes in the continuum emission (e.g., nonuniform illumination of the pseudophotosphere due to dynamical inhomogeneities such as temporarily hotter eddies or blobs). Particular attention is given to the contrast between the strong W-band (323.6-nm) excess presently observed in WR 6 (EZ CMa) and the FUV deficiency observed by van der Hucht et al. in 1974-1976; an explanation based on increased outer-envelope transparency is proposed.