The transparency of the Solar System to the Oort cloud comets

In long-term Monte Carlo simulations of the dynamics of the Oort cloud planetary perturbations cannot be taken directly into account. To do this we propose a simple approximation: estimating the Solar System transparency coefficient P measuring the probability for a comet to be removed from the cloud by planetary perturbations during a single perihelion passage. We estimated the value of this coefficient from the observed and artificial cometary samples. We excluded nongravitational forces fom our calculations. We obtained $P\cong0.25$ for inner cloud comets and $P\cong0.5$ for the outer and most active part of the cloud. The dependency of P on the comet observability limit ${\it OL}$ is also presented for various cometary samples.