Modelling interstellar extinction and polarization with spheroidal grains
arXiv:0801.1406 · doi:10.1016/j.jqsrt.2008.01.003
Abstract
We calculate the wavelength dependence of the ratio of the linear polarization degree to extinction (polarizing efficiency) $P(λ)/A(λ)$ from the ultraviolet to near-infrared. The prolate and oblate particles with aspect ratios from $a/b=1.1$ up to 10 are assumed to be rotating and partially aligned with the mechanism of paramagnetic relaxation (Davis--Greenstein). Size/shape/orientation effects are analyzed. It is found that the wavelength dependence of $P(λ)/A(λ)$ is mainly determined by the particle composition and size whereas the values of $P(λ)/A(λ)$ depend on the particle shape, degree and direction of alignment.
13 pages, 9 figures, aacepted for publication in Journal of Quantitative Spectroscopy & Radiative Transfer (special issue, X Conference on Electromagnetic & Light Scattering)