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F. Poulet (Obsv. Meudon), B. Sicardy (Obsv. Meudon/IUF Paris 6)
The system of Saturn's inner satellites is satured with many resonances. In addition, its structure should be strongly affected by tidal forces driving the satellites through several orbit-orbit resonances. The evolution of these satellites has been investigated using analytical and numerical methods. We show that the couple of satellites, Prometheus and Pandora, has a particularly short lifetime (< 20 millions of years). In those circumstances, passage of Pandora through resonance with Prometheus leads to a capture which increases the lifetime of the couple by a few tens millions of years. However, resonances in the system are not-well separated and capture results in chaotic motion. The secondary resonances are also invoked to disrupt resonant configurations. In all cases, the converging orbits of these two satellites result in a close encounter. The different outcomes of close encounter are then studied as a function of their orbital separation. From this, we derive that the most probable outcome is a catastrophic disruption of the satellites. The implications for the origin of the Saturn's rings will be presented.