CAOSP abstracts, Volume: 38, No.: 1, year: 2008

Abstract: The distant comet reservoir, the Oort cloud, is perturbed by the Galactic tide, nearly passing stars, and giant interstellar molecular clouds. The perturbations by the latter are least frequent, but their amplitude is expected to be highest. In this work, we suggest a simple model of a giant molecular cloud and investigate the gravitational effect of such an object, when the Sun with the Oort cloud goes across it. More specifically, we assume a molecular cloud consisting of a single or two spherical condensations, each with the density profile described by a Gaussian-distribution function. We demonstrate that the final perturbation effect of the molecular cloud on the comet reservoir is quite small. The directional distribution of comet orbits remains almost intact. The outer part of the comet cloud is eroded, but the erosion rate is not fatal for the cloud: we found the maximum rate of 22 % of the population. The erosion by the two-condensation molecular cloud is lower than that by a single-condensation molecular cloud, in the studied examples.