Experimental electrical resistivity values and computed thermal conductivities

We present a joint experimental-modeling investigation of core cooling in small terrestrial bodies. Significant amounts of light elements (S, O, Mg, Si) may compose the metallic cores of terrestrial planets and moons. However, the effect of multiple light elements on transport properties, in particular, electrical resistivity and thermal conductivity, is not well constrained. Electrical experiments were conducted at 10 GPa and up to 1850 K on high-purity powder mixtures in the Fe-S-O(+/-Mg, +/-Si) systems using the multi-anvil apparatus and the 4-electrode technique. The sample compositions contained 5 wt.% S, up to 3 wt.% O, up to 2 wt.% Mg, and up to 1 wt.% Si. We observe that above the eutectic temperature, electrical resistivity is significantly sensitive to the nature and amount of light elements. For each composition, thermal conductivity-temperature equations were estimated using the experimental electrical results and a modified Wiedemann-Franz law. These equations were implemen...