Spectroscopic Imaging of Evolved Star Envelopes

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The recent construction of radio millimeter wavelengths has permitted the imaging of outflows from stars in advanced stages of stellar evolution in lines of various molecules. This accomplishment permits the kinematics of these outflows to be studied, leading to an understanding of how nonspherical planetary nebulae form, as well as the chemical interactions between gas and dust particles as a function of distance. The Principal Investigator (PI) will use the "BIMA" radio array at Hat Creek, California and the new Arizona-German millimeter-wave telescope on Mt. Graham to study these questions. These studies are expected to lead to a better understanding of why about one half the planetary nebulae around these stars are significantly nonspherical and to lead to a better understanding of the chemistry of interstellar grains. The latter question is of importance to the thermodynamic conditions of interstellar gas and ultimately to the condensation of new generations of stars.//