This award supports cooperative research in the astronomy of comets by Walter Huebner of the Southwest Research Institute and P.D. Singh of the University of Sao Paulo in Brazil. They will measure the continuum radio emission from comets in the millimeter and centimeter wavelength range. These emissions may be explained as thermal radiation from aggregates of organic and refractory-silicate particles that radiate at a higher temperature than ice. In addition, they will investigate photodissociation and photoionization rate coefficients of selected heavy organic molecules and their decay products. The two scientists will develop a computer model for microwave thermal emission from these aggregates near the nucleus of several comets. This collaboration will be an excellent blend of theoretical and observational capabilities. Therefore the cooperation will benefit the field of cometary science as well as encourage and strengthen both Brazilian and U.S. astronomy.
