This award will support collaborative research between Dr. Peter A. Wehinger of Arizona State University, Tempe, and Dr. Bruce A. Peterson of the Mt. Stromlo and Siding Spring Observatories of the Australian National University, Canberra. The investigators intend to uncover new information about interstellar matter by determining the carbon isotopic abundance ratio in a sample of bright comets, and comparing that ratio to that in comet Halley; and to determine the abundance ratio in the local interstellar medium by observing absorption lines of molecules and molecular ions in the lines-of-sight of bright O- and B-type stars. Cometary abundance ratios are characteristic of the interstellar matter millions of years ago, and the two measurements will be compared, in order to illuminate the nature of the evolution of the interstellar matter. The project combines the expertise of the two investigators, both of whom are experts in the determination of spectra from astronomical measurements, and who have worked together to study the isotopic abundance ratio of Halley itself, at the Mt. Stromlo Observatory in Australia. In addition to giving providing new information about the composition of interstellar matter, advances in techniques for interpreting isotopic spectra may be expected from this research.
