THE CALCULATION OF CONTINUUM POLARIZATION DUE TO THE RAYLEIGH-SCATTERING PHASE MATRIX IN MULTI-SCATTERING AXISYMMETRICAL ENVELOPES

We have developed a numerical method to solve the polarized radiative transfer equation for scattering by particles with a Rayleigh phase ma trix in axisymmetric geometries. The method can treat an arbitrary num ber of scatterings, and provides a viable alternative to Monte-Carlo c alculations for the computation of continuum polarizations arising fro m Rayleigh scattering (or electron scattering) in axisymmetric envelop es. In the optically thin limit the computed polarization agrees with that predicted by the formula of Brown and McLean (1977). For models i n which multiple scattering is important, the results are in good agre ement with that obtained from an independently developed Monte-Carlo c ode. We have also verified that the transfer code yields, for several test cases, the polarized source functions in spherical geometry compu ted using the method of Cassinelli and Hummer (1971). Several test cas es are used to highlight the significant influence of multiple scatter ing and the albedo on the observed polarization.