Electrical Resistivity of FeS at High Pressures and Temperatures: Implications of Thermal Transport in the Core of Ganymede

Abstract

AbstractTerrestrial‐type planetary cores are thought to be predominantly composed of Fe with varying amounts of lighter chemical species or impurities chosen from a narrow range of possible elements, which includes S. These impurity elements may contribute significant effects to the transport properties of these cores, which have direct influence over dynamo and thermal evolution of the planetary body. Recent experimental methods have partially eased the substantial challenges that arise in direct measurements of electrical transport properties at high pressures and temperatures. In this study we show how this methodology can be used to measure the electrical resistivity of a sample in powder form. The electrical resistivity of FeS was measured in both solid and molten states at pressures up to 5 GPa and the thermal conductivity was calculated using the Wiedemann–Franz Law from the electrical measurements. The results showed FeS is notably more electrically and thermally conductive when compared to previous studies in both the solid and molten states. The results were used to estimate the adiabatic conductive heat flow of a molten FeS core model of Ganymede, which showed that thermal convection is permissible as a dynamo power source.