Optical properties of interstellar graphite and silicate grains
B. T. Draine, H. M. Lee;
ApJ, 1984, 285, 89
ABSTRACT:The dielectric functions for graphite and astronomical silicate material are computed using available laboratory and
astronomical data.
It is noted that the magnetic dipole contribution to absorption
in the infrared wavelengths can be important for conducting particles
such as graphite.
Formulas are given for evaluating electric and magnetic
dipole cross-sections for small particles.
Absorption cross-sections are
evaluated for graphite and silicate particles with sizes between 0.003 and 1.0
microns, and wavelengths from 300 A to 1000 microns.
On the basis of
polarization profiles computed for both prolate and oblate graphite-silicate
spheroids, it is concluded that interstellar silicate grain are predominantly
oblate.
Extinction curves are calculated for Mathis-Rumpl-Nordsieck
graphite-silicate grain mixtures and are compared to observations.
The model is found to
be in good agreement with available infrared observations.
KEYWORDS: granular materials, graphite, interstellar matter, optical properties, silicates, absorption cross sections, infrared astronomy, opacity, particle interactions, scattering cross sections
PERSOKEY:dust, polarisation, uv, absorption, ,
CODE: draine84