Radio Detection of H2O in Comet Bradfield (1974b)

Abstract

The present authors (Clark et al, 1971) previously attempted to detect the 1.35 cm microwave line of water in Comet Bennett (1969i) using the 26 m Maryland Point radio telescope of the Naval Research Laboratory. An upper limit for the H2O column density of 1017 molec/cm2 was obtained assuming the rotational levels were in thermal equilibrium, A more recent search in Comet Kohoutek using the 37 m radio telescope of the Haystack Observatory with a low noise traveling wave maser preamplifier was also unsuccessful. In this comet the identification of H2O+ in the visible spectrum gave strong support to the idea of water as a major parent molecule. The radio detection of HCN (Heubner et al, 1974) and CH3CH (Uhlich and Conklin, 1974) in Comet Kohoutek suggested that the attempt to detect H2O should be repeated in a suitable comet.