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S. D. Doty (MSCD)
Water is an astrophysically interesting molecule. Theoretically, it is both a proposed resevoir of oxygen and predicted to be an important coolant in molecular clouds. Observationally, strong water lines have been observed toward many sources, including masing toward Orion (Cernicharo et al.). In this paper, a detailed theoretical model for the thermal balance, chemistry, and radiative transfer in centrally heated molecular clouds (Doty and Neufeld) is applied to the 183GHz 3(13)-2(20) rotational transition of para-water. The model predictions are then compared to the observations to constrain the physical/chemical properties of the source. Implications for the water abundance near IRc2 are discussed. Foremost among these, it is found that gas-phase chemical models cannot reproduce the observations, confirming the role of shock/grain mantle chemistry in Orion.
The author(s) of this abstract have provided an email address for comments about the abstract: dotys@clem.mscd.edu