Abstract
Our knowledge of the gravity field of Titan has been recently improved thanks to the fly-bys of Cassini spacecraft, that provided us first values of Titan's J_2 and C_{22}, unfortunately without any indication of the polar inertial momentum C. Anyway, these data allowed us to give last year a first 3-dimensional description of the rotation of Titan, seen as a rigid body. In particular, we pointed out an interesting phenomenon forcing the wobble (i.e. the angular separation between Titan pole axis and angular momentum), that we suspected to be nearly resonant. This year we present a study of this resonance, involving a free libration around the Cassini equilibrium and a proper mode given by the orbital ephemerides. The resonant argument has been clearly identified, and its behaviour has been investigated using the Second Fundamental Model of Resonance. We show that in case of capture, the wobble might be pumped to several degrees. Moreover, we propose an original formula to estimate the contribution of the wobble in the tidal internal dissipation of a synchronous satellite. A significant wobble might cause a wrong estimation of the rotation of Titan.
| Original language | English |
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| Title of host publication | Scientific Highlights 2008 |
| Editors | F Casoli, T Contini, J. M Hameury, L Pagani |
| Publisher | EDP Sciences |
| Pages | 137-140 |
| Number of pages | 4 |
| Publication status | Published - 2008 |