Narrow-band photometry of comet Austin 1990 V

Abstract

Photometric observations of comet Austin 1990 V carried out at the Skalnaté Pleso Observatory on three nights of May 1990 are analysed and discussed. The comet was observed in the post-perihelion phase about two months after perihelion at heliocentric and geocentric distances of 1.201 and 0.244 AU, respectively. Emission band fluxes F e and continuum fluxes F c are presented, from which the total numbers of molecules M in the columns encircled by the diaphragms (39,000, 24,300, 14,400 and 8700 km in our treatment), are calculated. The production rates Q ν are estimated from the conventional Haser model. Comparing with published results it is found that the production rate of C 2 parent molecules after perihelion varies as r −2.1 and of CN as r −3.4. The results are in agreement with a suggestion that different formation mechanisms for the two radicals are present.