Since its arrival on July 1st of 2004, the Cassini spacecraft has revealed an astonishing and complex picture of the Saturnian system. Among the unexpected results are the high activity of Enceladus, a very rich and complex ring structure, and the internal ocean of Titan. Most of the satellites have unexpectedly high eccentricities, geologically young surfaces and active interiors. The mutual interactions between Saturn, its satellites and the rings determine the evolutionary history leading to its current dynamical configuration.
It is generally admitted that tidal dissipation is the most likely mechanism for both changing the orbits and heating the synchronously rotating satellites. The angular momentum transfer within the Saturn system is associated with the dynamical configuration like resonances and eventually the possible resurfacing rate of the satellites. Several satellites are in mean motion orbital resonances such as the pairs Dione and Enceladus, Mimas and Tethys. The undamped eccentricities and inclinations of the satellites can be due to past or present resonances.
The Saturn system raises several open questions such as the origin of mechanisms of satellite resurfacing, coherent scenarios for capture into resonance for different pairs of satellites and the initial state of the rings. All these questions motivate global dynamical studies that take into account the tidal interactions and secular variations of the orbital parameters.
Our international scientific team is composed of experts from different fields related to planetary sciences (including astrometry of the Solar system objects, orbital and rotational dynamics, physics of tidal dissipation in planetary and stellar interiors). First, using the accurate positions of Saturn’s satellites observed for more than a century and adding the new Cassini data, our team will provide updated secular variations of the orbital elements of the satellites that are to be related to internal dissipation processes, via the quality factor Q. Second, the past orbital history of the Saturn system will be revisited, including Enceladus’ tidal dissipation and ring interactions. Finally, new results concerning the resurfacing and interior modeling of the satellites will be produced.