A Search for Molecular Transitions in the 22-25 GHz Band in Comet Kohoutek 1973f

Abstract

According to current theories, the radicals optically identified in cometary spectra stem from more complex parent compounds which have no transitions at visible wavelengths. In recent years radio transitions of likely molecules have repeatedly been searched for but were never found (e.g., Huebner and Snyder, 1970; Clark et al., 1971). Only in Comet Kohoutek 1973f have microwave lines of three molecules been detected, OH (Biraud et al., 1974; Turner, 1974), CH3CN (Ulich and Conklin, 1974), and HCN (Snyder et al., 1974). Here we report on our search for transitions in the 22-25 GHz band of the molecules H2O, NH3, and CH3OH in this Comet and give upper limits on line temperatures and column densities.