Thermal Modeling of Europa’s Interior Using Finite Element Method

Europa’s interior structure and geological evolution are governed by its thermal state, which controls phase stability, rheology, and heat transport from the core to the surface. Assuming a cold accretion model proposed by Trinh et al (2023),we present a one dimensional spherical finite element thermal model that resolves Europa’s metallic  Fe - FeS core, silicate mantle with composition consistent with peridotite, convecting subsurface ocean, and outer ice shell. The model assumes radial symmetry, homogeneous layer compositions and constant material properties within each region.The model enforces spherical symmetry via a zero - flux Neumann boundary at the core center and imposes a fixed surface temperature of -160 °C to represent radiative equilibrium. Heat transfer is treated as conductive in the core and ice shell, while mantle and ocean convection are parameterized through effective thermal conductivity enhancements. Radiogenic heating within the silicate mantle and tidal dissipation uniformly distributed in the ice shell provide the primary internal heat sources. Monte Carlo sampling of ice shell thickness captures uncertainty in the near - surface thermal structure. Notably, the model excludes retained primordial heat from accretion, adopting present-day thermal boundary conditions. Resulting temperature profiles reveal a peak core temperature near 1660 °C, consistent with solid or near-solid Fe - FeS alloy at Europa’s core pressures (3-6 GPa). The mantle temperature decreases smoothly from ~1600 °C at the core - mantle boundary to ~400 °C at the mantle - ocean interface, indicating a solid, sluggishly convecting silicate mantle without evidence of wholesale melting. Temperatures near the mantle - ocean boundary could promote sustained water-rock interactions and potential hydrothermal circulation, leading to serpentinization along the ocean floor. The ocean exhibits a near - isothermal temperature profile, remaining fully liquid in all realizations due to sufficient internal heat flux. The ice shell shows a steep thermal gradient, with temperatures declining from near - melting at its base to ~-160 °C at the surface, consistent with a mechanically stratified ice shell.