Solid state convection is expected to influence the evolution and the geological activity of Ganymede [1]. The spatial distribution of tidal dissipation could influence the temperature structure of the outer ice shell and, likely, the internal processes and the geological activity. We investigate the influence of the tidal dissipation on a convective ice shell of Ganymede. We use the finite-element code ASPECT [2] to solve the Boussinesq fluid equations of the conservation of continuity, momentum and energy to simulate solid-state convection within the ice shell of Ganymede. The numerical simulations are performed in a 2-dimensional cylindrical geometry. We adopt a temperature-dependent Newtonian viscosity for the water ice, assuming diffusion creep. The spatial distribution of the tidal dissipation rate is computed adopting a Maxwellian material model [3, 4]. Preliminary results show how the convective patterns, and the thermal plumes are influenced by the spatial distribution of the tidal dissipation. We also discuss how radar sounder investigations with RIME instrument [5] on board of the ESA’s JUICE mission in combination with radio science measurements of the gravity field by 3GM experiment [6] could characterize the thermal structure of Ganymede’s ice shell.

This study presents geodynamic experiments within the outer ice shell of Ganymede to investigate the effects of partial melting into the convective layer, and trying to infer any correlation between internal processes and strain deformations in surface regions such as cryovolcanism and polar deposits. The numerical models were conducted performing a sensitive analysis of the internal dynamic for compressible fluids by varying the viscosity, ice shell thickness, pressure at the melting point of ice, and applying the Anelastic Liquid Approximation (ALA). Results show molten material under restricted geophysical parameters that could allow for emerging material from the subsurface ocean to the surface. These findings will support the objectives of the RIME instrument on board of the JUICE mission, as they point out specific conditions that may, in the future, help to have a better understanding of the internal mechanisms that transfer heat on the surface and modify the geomorphology and atmospheric processes.

In this manuscript, there were performed simulations of the evolution of the surface temperature for each of the two hemispheres of Iapetus. This icy moon of Saturn shows the most differentiated albedo dichotomy of the Solar System. The dark leading side has a lower albedo than the bright trailing side. Spectral data on the visible light reveal the existence of two types of materials on the surface. The darkening in the leading side is thought to be due to the presence of organic material and carbonaceous compounds on the surface, while the trailing side is covered by water ice due to migration processes from the dark side. On airless bodies like Iapetus, the surface escape speed is greater than the speed of water molecules, resulting in the retention of a H₂O atmosphere that allows some species to diffuse through it. Results showed a slow yet steady increment of temperatures for both sides, with a steeper slope for the dark hemisphere. It was also simulated how much energy can be accumulated on both sides and the consequences of that. Finally, we calculated the diffusion coefficients for ammonia, methane, and water ice. The results allowed us to infer how these compounds could evolve over time.

Iapetus, a Saturn moon, shows the most differentiated albedo dichotomy of the Solar System. The dark leading side has a lower albedo than the bright trailing side. Spectral data on the visible light reveal the existence of two types of materials on the surface. The darkening in the leading side is thought to be originated by the presence of organic material and carbonaceous compounds on surface, while the trailing side is covered by water ice due to migration processes from the dark side. On airless bodies like Iapetus, the surface escape speed is greater than the speed of water molecules, resulting in the retention of a H2O atmosphere that allows some species to get diffused through it. Here, there were performed simulations of the evolution of the surface temperature for each of the two hemispheres of Iapetus. The results showed a slow yet steady increment of temperatures for both sides, with a steeper slope for the dark hemisphere. It was also simulated how much energy budget can be accumulated in both sides and its consequences. Finally, we calculated the diffusion coefficients for ammonia, methane, and water ice. The results let us infer how these compounds could evolve over time.

On Enceladus, the first sign of water vapor plumes was detected by the UVIS instrument of Cassini during a stellar occultation in July 2005. The dynamics of these water plumes, probably related to the ocean activity, are an important subject of study in order to understand the exchange of material from this ocean into the atmosphere. There are different theories that might explain the physical processes that allow for the expulsion of material from the subsurface. The formation of these jets could be produced by the sublimation of ice (temperatures below 273 K) rising beneath the hydrostatic pressure along the ice layer or can come from underground boiling liquid that erupts through vents. Other hypothesis assumes that there are regions where the pressure can drop below the saturation vapor pressure of the liquid, allowing for it to boil, so it can produce a pocket of gas in equilibrium with ice grains and liquid water. Another possibility is that the thermal activity in the seafloor of Enceladus creates hot water outflows that locally affect the ice shell and the thinner icy crust in the polar region due to tidal stress. This work presents another possible model for the formation of these vapor plumes. The hydro cyclonic flow could be also a mechanism that produces a constant ejection of these jets and contributes to atmospheric processes. Here we describe a simulation of the dynamic of the energy budget into the atmosphere. Enceladus is tidally locked with Saturn, making the moon spinning around the planet always showing the same face, generating in this way a difference in temperatures between the internal side and the external one. This contrast of temperatures might produce a movement of violent flows of jets on the equator similar to the storms observed on Jupiter. If the tidal axis is not aligned with the major axis, the tidal forces exert a net momentum on the moon, forcing a realignment of the orbit. The result of these processes is a hydro cyclonic flux in the shape of a tornado that eventually generates, due to pressure differences, a straight upwards constant flow that separates the fine particles rising towards the surface from the heavy ones sinking towards the ocean. This hydro cyclonic type of flow might explain the constant jets from the tiger stripes on Enceladus that could decrease when the energy flux received from the sun drops due to the distance between Saturn and the Sun, and the atmospheric and physical conditions are stable.