Thermal-orbital histories of viscoelastic models of Io (J1)

Three distinct successive states are noted in the present thermal-orbital histories of Io viscoelastic models, which possess dissipation over the entire uniform mantle: (1) a hot, high-dissipation state, (2) an oscillatory state with oscillations of the thermal-orbital variables, and (3) a cold, low-dissipation state. It is suggested that Io may currently be in the thermal-orbital near-equilibrium state (i.e., state 1) for reasonable values of the mantle rheology parameters. The time-dependence of convective heat transport should be important for the present Io, and may increase the acceptability of the equilibrium hypothesis. 60 refs