Pre- and Post-Perihelion Spectroscopic Observations of Comet Kohoutek (1973f)

Abstract

AbstractTwenty pre- and post-perihelion calibrated image-tube spectrograms (3400-9000A; 75 and 150 A/mm) were obtained of Comet Kohoutek covering a range in heliocentric distances of 0.9 to 0.4 a. u. (30 November 1973 - 14 February 1974). Total band intensities have been measured for the CN, C2 and NH2 bands in the coma spectrum, and for the CO+ and H2O+ bands in the tail spectrum. Changes in the total band intensities as a function of heliocentric distance are discussed, as are the pre- and post-perihelion characteristics of the spectra. The line intensity distributions within individual bands of the heteronuclear molecules (with large dipole moments) indicate very low rotational “temperatures” as expected. The measured band intensity ratios of the A2π-X2Σ (red) CN bands and the B2Σ-A2π (violet) CN bands are compared with predicted band intensity ratios calculated by T. Danks and C. Arpigny (1973 Astron. and Astrophys. 29, 347). Finally column densities are determined for CN and C2 in the coma and CO+ in the tail of Comet Kohoutek at various heliocentric distances.