Narrowband Photometry of Comet Austin 1990V

The results of photoelectric photometry with the narrowband CN, C3, C2, blue continuum, and ultraviolet continuum IHW interference filters are presented. The observations were carried out with a set of diaphragms of different radii. Vectorial Monte Carlo modeling of the cometary coma was used for the determination of production rates of the radicals, the parent and daughter lifetimes, and the daugher ejection velocities from the parents. The CN and C2 parent lifetimes (at 1.0 AU) were 2.7 ± 1.3 × 104 and 2.3 ± 0.6 × 104 sec, respectively, and the lifetimes of CN, C3, and C2 molecules were 2.1 ± 3.0 × 105, 1.8 ± 2.0 × 105, and 1.1 ± 0.4 × 105 sec (at 1.0 AU), respectively. The daughter ejection velocities from parents were 2.6 ± 1.2 km sec-1 for the CN and 0.1 ± 0.8 km sec-1 for the C2 molecule. The dependence on heliocentric distance of the molecules and dust production rates in the range of 0.7 ÷ 1.0 AU was described by the power law function r-nh . The power index was 2.97 ± 0.11 for CN, 2.34 ± 0.55 for C3, 2.44 ± 0.17 for C2, and 3.44 ± 0.51 for dust. Relative abundances of CN and C3 for Comet Austin at 1.0 AU postperihelion were similar to the "normal" ones with some enrichment of the C2 molecule.