Long term dynamical evolution of the Oort cloud comets: galactic and planetary perturbations

The source of long-period comets can be numerically modeled by means of Monte Carlo simulation of the Oort cloud dynamics. Tracing a comet motion under the galactic per- turbations over a long time interval requires taking into account of planetary perturbations. A method for the approximate treating of the planetary perturbations in such simulations is de- scribed. Some peculiarities found in planetary action on long-period simulated cometary sample are also discussed.