Comet Halley O( 1D) and H 2O production rates

Abstract

Ground-based observations of Comet Halley [OI]6300 were carried out using the Wisconsin dual-etalon Fabry-Perot spectrometer at the McMath solar telescope on Kitt Peak. The field of view diameter on the sky was approximately 7′ preperihelion and 10′ postperihelion. Spectral scans were acquired at a resolution of 0.2 Å, which was sufficient to resolve cometary [OI]6300 emission from nearby cometary NH 2 and telluric [OI]6300 emissions. From these measurements, we determined the production rate Q( O( 1 D)) . By taking into account photodissociation of H 2O and OH as sources of O( 1D), we find that the ratio Q( H 2 O) Q( O( 1 D)) is 6 and obtain Q(H 2O) from our Q( O( 1 D)) measurements We compare our Q(H 2O) results with measurements by other groups.