OPTICAL-PROPERTIES OF 2-LAYERED SPHEROIDAL DUST GRAINS

The cross sections for extinction and linear and circular polarization s are calculated for individual two-layered spheroids with various rat ios of the volume of the core to the total volume of the particle, V-c ore/V-total. It is shown that the appearance of a small silicate core in an ice particle strongly affects its optical properties. Starting f rom V-core/V-total approximate to 0.75, the optical properties of two- layered spheroids differ only slightly from the properties of homogene ous silicate particles. An increase in the relative volume of the core produces similar changes in the polarization, regardless of the shape and type (prolate/oblate) of the particle.