POLARIZATION CANCELLATION IN THE 2-COMPONENT WINDS FROM WOLF-RAYET STARS

It has been suggested that the Wolf-Rayet wind momentum problem can be resolved by assuming that these stars have rotationally enhanced equatorial outflows. The resultant asymmetry of the electron envelope would naturally lead to an intrinsic polarization of the stars. Some, but not all, WR stars are highly polarized. On average, these stars are not as highly polarized as the Be stars, for which there is strong evidence for dense equatorial winds. In addition, the wavelength dependence of the polarization from a WR star in the ultraviolet is different from that expected from an equatorial circumstellar disk of electrons. In this paper we explore the possibility that there can be at least partial cancellation of the equatorial disk polarization as a result of scattering from the electrons that are present in the strong polar wind of WR stars. In order to achieve the cancellation necessary to explain the wavelength-dependent polarization, the polar wind must have a mass-loss rate that is near the maximum that is supported by radiation-driven wind theory. In addition, we find that it is possible to derive important new information regarding the relative column masses of the polar and equatorial winds.