Circular polarization from scattering by circumstellar grains

It is suggested that observations of circular polarization can be a valuable tool for the study of circumstellar nebulae. A simple model is presented to predict the percentage of circular polarization produced by scattering from the dust contained within such nebulae; it was found that a significant component of circular polarization can be produced in nebulae which have a net linear polarization. Possible observations of the red supergiants mu Cep and alpha Ori are given as examples.