CHAOTIC DIFFUSION AND THE ORIGIN OF COMETS FROM THE 2 3-RESONANCE IN THE KUIPER BELT/

The dynamical structure of the 2/3 resonance at small inclination is e xplored using numerical integrations of test particles to compute the evolution of proper elements with time. The basic features are related to the analytically computed geography of secular resonances. This pa per focuses on the existence of slowly diffusing chaotic orbits, which escape from the 2/3 resonance after billions of years. The origin of short-period comets may be related to the existence of such orbits. We numerically determine the rate at which 2/3 resonant objects are deli vered to close encounters with Neptune. From this result we estimate t he number of comet-sized objects that should presently be in the 2/3 r esonance to explain the influx rate of observed short period comets; t he result of 10(8) to 10(9) seems to imply that 2/3 resonant bodies sh ould be collisionally evolved. (C) 1997 Academic Press.