THE THEORETICAL POLARIZATION FROM AXISYMMETRICAL CIRCUMSTELLAR ENVELOPES WITH CONSTANT SCATTERING OPTICAL DEPTH

The single-scattering of light through an axisymmetric, optically thin envelope with iso-scattering optical depth is considered. The maximum theoretical polarization of Wolf-Rayet and Be stars is then investigated using three geometrical model envelopes that are frequently encountered in the literature: a two-component wind, a wedge-shaped disc and an oblate spheroid. The degree of polarization from such envelopes is found to be P less-than-or-equal-to 0.6 per cent, consistent with observations of WR stars but not with those of Be stars, suggesting that the model is not consistent with the astrophysics of Be stars.