Tidal Heating in a Subsurface Magma Ocean on Io Revisited

Abstract We investigate the tidal dissipation in Io's hypothetical fluid magma ocean using a new approach based on the solution of the 3D Navier‐Stokes equations. Our results indicate that the presence of a shallow magma ocean on top of a solid, partially molten layer leads to an order of magnitude increase in dissipation at low latitudes. Tidal heating in Io's magma ocean does not correlate with the distribution of hot spots, and is maximum for an ocean thickness of about 1 km and a viscosity of less than 10 4 Pa s. Due to the Coriolis effect, the k 2 Love number can depend on the harmonic order. We show that the analysis of k 2 may not reveal the presence of a fluid magma ocean if the ocean thickness is less than 2 km. If the fluid layer is thicker than 2 km, k 20 ≈ k 22 /2 ≈ 0.7.