The planet Uranus and its satellites form one of the most mysterious systems in our Solar System. Geological traces of global resurfacing of the main satellites and the abnormally relatively high values of some of their orbital elements suggest a rich dynamical evolution. The orbits are expected to slowly drift away owing to tides raised on the planet. As a result, several mean motion resonances (MMR) between the satellites were likely encountered in the past. In this presentation, we address the dynamical and tidal evolution of the five major satellites of Uranus, namely, Miranda, Ariel, Umbriel, Titania, and Oberon.

Resorting to an N-body model that takes into account the tidal evolution of the orbits and the spins of all bodies, we have shown that, since the 5/3 Ariel-Umbriel MMR, the evolution of the system is not disturbed. We also developed a secular two-satellite model to study in detail the passage through the 5/3 Ariel-Umbriel MMR, both analytically and numerically. By performing a large number of numerical simulations, we have shown that the eccentricity of Ariel (e1) is the key variable to evade the 5/3 MMR. We have also shown that, to replicate the currently observed inclinations of Ariel (I1 = 0.0167◦) and Umbriel (I2 = 0.0796◦ ), the initial inclinations of both satellites must be I1 ≤ 0.05◦ and I2 ≈ 0.082◦. These initial inclination values are similar to the currently observed.

Organized by: Catarina Cosme