Orbital Evolution of Retrograde Cometary Dust Particles

J.-C. Liou (GB Tech Inc.), H. A. Zook (NASA/JSC), A. A. Jackson (LPI)

The orbital evolution of dust particles from retrograde comets are numerically calculated. The results show that trapping into mean motion resonances (MMRs) with planets dominates their orbital evolution. This feature is similar to that of dust grains in prograde orbits. However, an unusual phenomenon was observed in the numerical simulation. While trapped in an MMR, a dust grain can evolve from retrograde orbit to prograde orbit. Based on an analytical theory of particles trapped in MMRs with a planet (Liou and Zook 1997, Icarus, in press), it is possible for such a transition to occur. It is, however, impossible for a prograde orbit dust grain to evolve into retrograde orbit while trapped in an MMR.