Inferring Io’s interior from tidal monitoring

Io’s spectacular volcanic activity involves strong tidal dissipation in its interior. Magnetic induction measurements and surface observations of the indicate presence significant melt interior, but distribution remains unconstrained. Tidal deformation a planetary body is strongly related to rheological properties thus, larger extent, content. The amplitude may be monitored by future missions from spacecraft tracking, altimetry high-resolution imaging, giving access potential displacement Love numbers k2, h2 l2. To anticipate such measurements, we compute response described both shear bulk viscoelastic rheology for various distributions within We show that heating between mantle asthenosphere very sensitive assumed fraction asthenosphere. For smaller critical value called (ϕc), corresponding transition solid-dominated behavior liquid-dominated one, mostly occurring mantle. this mantle-dominated regime, viscosity solid rock matrix than 1017–1018 Pa s required reproduce estimated heat output (ranging 65 125 TW). slightly above ϕc, occurs asthenosphere, resulting radical change pattern characterized reduction polar contribution. Despite clear transition, changes terms l2 are subtle would require high precision measurements. k2 only mainly density metallic core, with number potentially as 0.1 low core below 0.06 core. especially more distribution, distinction asthenosphere-dominated regimes, difference amplified contribution response. combined detection (>0.2) (>0.07) values (<0.1) confirmation plays crucial role budget Io will provide constraints on thickness (< 100 km) (>ϕc) partially molten Accurate determination numbers, libration magnetic measurement profile