Evolution of the Oort cloud due to stellar encounters

Abstract

Planetesimals with great semimajor axes by planetary scattering form the spherical Oort cloud due to the Galactic tide. However, the distribution of the inclination is not isotropic. Passing stars, that have random-wark nature, may play an important role in producing an isotropic distribution of the inclination. Using the impulse approximation, we analytically examine the effects of stellar encounters on the orbital evolution of planetesimals. For the initial condition, we use a flat planetesimal disk on the ecliptic plane formed by planetary scattering.