The Internal Structure of Io

Io is a differentiated body with a silicate crust and mantle, and an iron-rich core. However, its internal structure, especially that of its mantle, differs from that of other terrestrial bodies, as a result of the intense heat supply by tidal dissipation. The amount and distribution of melt in Io’s interior strongly depend on the composition, as well as the heat and mass transport mechanisms operating at depth and in the near-surface. This article discusses melting processes and the mechanisms of magma segregation inside Io, informed by Earth-based observations and spacecraft measurements, as well as thermochemical and thermo-physical modeling.