17 research outputs found
Modelling interstellar extinction and polarization with spheroidal grains
We calculate the wavelength dependence of the ratio of the linear
polarization degree to extinction (polarizing efficiency)
from the ultraviolet to near-infrared. The prolate and
oblate particles with aspect ratios from 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 is mainly determined
by the particle composition and size whereas the values of
depend on the particle shape, degree and direction of
alignment.Comment: 13 pages, 9 figures, aacepted for publication in Journal of
Quantitative Spectroscopy & Radiative Transfer (special issue, X Conference
on Electromagnetic & Light Scattering
Optical properties of dust
http://arxiv.org/abs/0808.4123Except in a few cases cosmic dust can be studied in situ or in terrestrial laboratories, essentially all of our information concerning the nature of cosmic dust depends upon its interaction with electromagnetic radiation. This chapter presents the theoretical basis for describing the optical properties of dust -- how it absorbs and scatters starlight and reradiates the absorbed energy at longer wavelengths.Partial support by a Chandra Theory program
and HST Theory Programs is gratefully acknowledged