Silicates and Variability in Comets Okazaki-Levy-Rudenko (1989r) and Austin (1989c1)

Comet Okazaki-Lcvy-Rudcnko (1989r) was studied over a wide range of wavelengths from the UV to the submillimeter. Using visual magnitude estimates from the IAU Circulars and reported submillimeter fluxes in conjunction with our thermal IR spectroscopy and filter photometry, the nature of the grains and the behavior of the comet can be assessed and compared to other comets studied under this program. In addition, preliminary results from a collaborative IR study of Comet Austin arc presented which address the nature of the dust in that comet. Progress on a model for cometary properties and brightness behavior is discussed.