DETERMINATION OF THE ORTHO-PARA RATIO AND NUCLEAR SPIN TEMPERATURE FROM HIGH RESOLUTION WATER FLUORESCENCE SPECTRA OF COMETS HALLEY AND WILSON

$^{1}$ M.J. Mumma, H.A. Weaver, H.P. Larson, D.S. Davis, and M. Williams, Science 232, 1523-1528 (1986).Author Institution: Molecular Spectroscopy Laboratory, Department of Physics and Astronomy, The University of Tennessee; Planetary Systems Branch, NASA Goddard Space Flight Center; Planetary Systems Branch, Space Telescope Science Institute; Lunar and Planetary Laboratory, The University of Arizona; Max Planck Institute, Federal Republic of GermanyHigh resolution water fluorescence spectra in the $\nu_{3}$ band has been observed from comets Halley and Wilson. The observations were made aboard NASA's Kuiper Airborne Observatory with the University of Arizona high resolution Fourier transform $spectrometer.^{1}$ Using a straight forward radiation transfer model of the cometary coma, we have analyzed the $\nu_{3}$ fluorescence data. A rotationally equilibrated, aperature-averaged coma is assumed. An effective rotational temperature and ortho-para ratio for water in the coma are determined. Results for comets Halley and Wilson will be presented. The implications of an ortho-para ratio significantly different from 3:1 will be discussed