Spitzer Space Telescope - Theoretical Research Proposal #20109


Optical Properties of Cosmic Dust Materials

Principal Investigator: Joseph Weingartner
           Institution: George Mason University

Co-Investigators: 
Gary Ferland, University of Kentucky                                  

Science Category: ISM 
Dollars Approved: 48191.0 

Abstract:
Many cosmic dust materials exhibit identifying spectral features in
the infrared, and laboratory work has provided detailed infrared
optical properties for numerous materials of astrophysical importance.
Thus, the Spitzer Space Telescope is a powerful tool for determining
the grain constituents in a wide range of cosmic environments,
including protoplanetary disks, outflows from evolved stars,
supernovae, star-forming regions, and active galactic nuclei.  Dust is
important both in the physics of these objects and as a diagnostic.
For example, dust absorbs short-wavelength radiation and re-emits at
longer wavelengths, and often dominates the heating or cooling of the
gas.  Thus, detailed interpretation of the spectrum, originating in
both gas and dust, is only possible if the optical properties of the
dust materials are known across the entire electromagnetic spectrum.
We propose to construct X-ray to far-infrared (FIR) dielectric
functions for a host of important dust materials, consistent with all
available constraints (from laboratory data, basic physical
principles, and astronomical observations).  These materials include a
variety of silicates, oxides, and sulfides.  The optical properties
will be made available on the World Wide Web and will be incorporated
into the spectral simulation code CLOUDY.