95-28256 McCray Dr. McCray will continue to develop theoretical tools for analyzing the spectra of supernovae. This analysis is particularly valuable during the nebular phase, a few months after the initial outburst, when the supernova debris has thinned enough to observe all the newly-synthesized elements created in the explosion. The spectrum is decoded using a theoretical model of spectrum formation. This project will concentrate on two specific projects. The first is to complete the development of comprehensive models to describe the evolution of the spectrum of SN1987A, especially the transfer and fluorescence of the ultraviolet radiation. The second is to develop theoretical models for the nebular spectra of Type Ia supernovae. There are indications that this might be a reliable method for calibrating the true luminosity of such sources, thus providing standard candles with which distances to galaxies can be determined. ***
