  We present results of a study aimed at deriving fundamental properties of
circumstellar debris disks from observed infrared to submillimeter spectral
energy distributions. This investigation is motivated by increasing
telescope/detector sensitivity, in particular the expected availability of the
Space Infrared Telescope Facility (SIRTF) followed by the Stratospheric
Observatory for Infrared Astronomy (SOFIA), which will enable detailed studies
with large source samples of late stage circumstellar disk and planetary system
evolution. We base our study on an analytic model of the disk density
distribution and geometry, taking into account existing constraints from
observations and results of theoretical investigations of debris disks. We also
outline the effects of the most profound characteristics of circumstellar dust
including the grain size distribution and dust chemical composition.
