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J. L. Highberger, D. Arnett, L. M. Ziurys (University of Arizona), S. Petrie (Australian National University)
We have developed a new chemical model to calculate the abundances and distributions of metal-containing molecules (in the chemist's sense) in the circumstellar envelopes of Asymptotic Giant Branch stars. Initial abundances of the elements at the surface of the star are computed using the TYCHO nucleosynthesis code developed at the University of Arizona. Hydrodynamic mixing has been considered in the calculations. Abundances for elements with A < 30 have been computed for carbon rich stars between 1 and 8 solar masses. A chemical code has been developed using these initial abundances, based on reaction rates from the UMIST database. Radiative association reactions of metal species are included in the chemical network. Abundances as a function of distance from the central star are predicted for over 30 different chemical compounds. Model results will be compared to theorectical predictions of metal compound formation, as well as current observations.