Abstract:
Numerical computations show that: (1) the polarimetric behavior of carbon stars is inconsistent with the scattering by graphite grains, (2) the radial pulsation of the star does not significantly change the net polarization produced by an envelope, (3) the envelope geometry has very little effect on the normalized wavelength dependence, and (4) if the illuminating star has a nonuniform surface brightness distribution, circumstellar grain scattering produces not only significant changes in the normalized wavelength dependence of polarization but also polarization changes across spectral features.