UC Santa Cruz

Tidal dissipation in satellites affects their orbital and rotational evolution and their ability to maintain subsurface oceans. However, a satellites dissipation rate, parameterized by k2/Q, is hard to measure and is only known for the Moon and Io. Here, we use Titans measured departure from its expected rotation state to infer k2/Q and its boundary layer dissipation parameter K/Cs. Over the likely range of ocean and ice shell thicknesses, we infer a K/Cs of 6.3 × 10-14 s-1 to 2.4 × 10-10 s-1, a k2/Q of 0.058 to 0.12, and a minimum dissipation factor Q ≈ 5. Titans dissipation parameters are one to two orders of magnitude larger than the Moons and suggest an interior with a low effective viscosity. Titans dissipation rate implies that its eccentricity and inclination are damping rapidly, consistent with an excitation within the last ~350 Myr. The forthcoming Dragonfly lander could measure Titans tidal response, and JUICE could use our approach to determine Ganymedes k2/Q.