Modelling thermal evolution of molten and tidally heated Io-Like planetary mantles

Internal heating in rocky bodies shape their interior and surface characteristics as well as their evolution. Among internal heat sources, tidal dissipation is a key one. The most striking evidence in the Solar System is the case of Io, archetype of tidally-heated world hosting extreme volcanism.

Io’s internal dynamics is complex due to the large and tidally-produced heat flux, leading to widespread melting in the interior. For Io-like bodies, the dissipation and heat transport models have thus to incorporate interactions between solid and liquid phases. Io’s mantle is commonly modelled either as a solid convective mantle, adapting models of terrestrial planets, or as a fluid magma ocean, adapting models of fluid water oceans of icy moons. However, neither of these two classifications likely accurately describes Io’s partially molten interior.

In that context, we model Io's mantle thermal evolution following the work of Sanchis et al (2022, EPSC), who developed a magma ocean modelling, using the CHIC convective code (e.g. Noack et al. 2013, Infocomp). In addition, we take into account heat generated by tidal dissipation accounting for the effect of melt presence on the viscous and elastic parameters of the mantle following Kervazo et al. (2021).

Our study provides valuable insights into the role of a large amount of melt in the thermal evolution of rocky planets and moons, and our modeling approach is applicable to other rocky planets with hot interiors, including the Trappist-1 planets and various known rocky exoplanets.