Escape Velocities from Unstable Triple Stars

Abstract

In order to investigate a possible origin for stars with high peculiar velocities in the thick disc of our Galaxy, the dynamical evolution of 16 000 three-dimensional triple systems which consist of a binary with equal or comparable masses of componentsM1andM2and a low-mass third bodyM3is considered. We examine an extensive range of initial conditions with positions of the bodyM3randomly distributed around and inside the binary orbit.M3was given the initial radial velocityV0with respect to the center of inertia of the binary. The following dynamical system of units is used in this work: the unit of distance is the semi-major axis of the binary orbit, the unit of time is the period of the binary; the universal constant of gravity is unity. In these units the total mass of the close binary is 4π2.