On the dynamic stability of Saturn's F ring

We explore the dynamics of Saturn's F ring by following the orbital histories of circumplanetary particles between the orbits of Prometheus and Pandora. Our goal is to find structures that could be related to the F ring. Using a 3-D mapping integrator developped by Sicardy and Foryta (1996), we follow the behavior of several thousand test particles distributed unformly between 140,000 and 140,400 km in order to acquire a general picture of the dynamics of this zone. The model includes the gravitational effects of Saturn (up to J[SUB]4[/SUB]) and the two shepherd satellites. The numerical simulations show chaotic behaviors of the particles resulting in a close encounter with one or the other of the satellites, which deplete the zone between the satellites. The timescale over which particles are removed by the satellites is of order a ten thousand years. After a hundred thousand years, some particles exist but they are not related to the actual four strands of the F ring. As suggested by Cuzzi and Burns (1988), these simulations indicate that this ring may be a transient event occuring at the edge of the Roche limit. However, taking into account dissipation (collisions, viscosity) might help to explain the longevity and the location of this ring. This work was performed while the author held a National Research Council - NASA ARC Research Associateship.