Librations and obliquity of the largest moons of Uranus

• DOI: 10.1016/j.icarus.2024.116371
• Publication Date: 2024-11-17T06:35:55Z
• Authors: Rose-Marie Baland; Valerio Filice; Sébastien Le Maistre; Antony Trinh; Marie Yseboodt; Tim Van Hoolst
• Keywords: Physics - Geophysics; Earth and Planetary Astrophysics (astro-ph.EP); FOS: Physical sciences; Astrophysics - Earth and Planetary Astrophysics; Geophysics (physics.geo-ph)

Following the discovery of several ocean worlds in the solar system, and the selection of Uranus as the highest priority objective by the Planetary Science and Astrobiology Decadal Survey 2023-2032, the five largest moons of Uranus (Miranda, Ariel, Umbriel, Titania and Oberon) have been receiving renewed attention as they may also harbor a subsurface ocean. We assess how rotation measurements could help confirm the internal differentiation of the bodies and detect internal oceans if any. Because of the time-varying gravitational torque of Uranus on the flattened shape of its synchronous satellites, the latter librate with respect to their mean rotation and precess with a non zero obliquity. For a range of interior models with a rocky core surrounded by a hydrosphere, either solid or divided into an outer ice shell with a liquid ocean underneath, we compute their diurnal libration amplitude and obliquity.<br/>Paper accepted for publication in Icarus<br/>