Narrowband photometry of comet Austin 1990V

Waclaw Waniak, Pawel Magdziarz, Maciej Winiarski
Astronomical Observatory, Jagiellonian University, ul. Orla 171, Krakow, Poland

The results of photoelectric photometry with the narrowband CN, C3, C2, Blue Continuum (BC) and Ultraviolet Continuum (UC) IHW filters are presented. Comet was observed through a set of diaphragms of different radii. Vectorial Monte Carlo model of the molecular coma was used for the determination of production rates of the radicals, the parent and daughter lifetimes, and the daughter ejection velocities from the parents. The CN and C2 parent lifetimes (at 1.0 AU) were 2.7 ± 1.3 10^4 s and 2.3 ± 0.6 10^4 s respectively, and the lifetimes of CN, C3 and C2 molecules were 2.1 ± 3.0 10^5 s, 1.8 ± 2.0 10^5 s and 1.1 ± 0.4 10^5 s. The daughter ejection velocities from parents were 2.6 ± 1.2 km / s for the CN and 0.1 ± 0.8 km / s 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 rh^-n.with the power index equal to 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.