Implications for the energy source for an early dynamo in Vesta from experiments on electrical resistivity of liquid Fe-10wt%Ni at high pressures

Abstract

The electrical resistivity of Fe-10wt%Ni was measured at pressures 2–5 GPa at temperatures into the liquid state and compared to results of previous studies of pure Fe and pure Ni. Thermal conductivity was calculated from electrical resistivity to determine adiabatic core heat flux. The results are applied to determine whether thermal convection could be responsible for the putative dynamo in early Vesta's core. An adiabatic core heat flux of ~350 MW at the top of Vesta's core is estimated from this study and compared to a range of estimates of heat flux through the CMB of 1.5–78 GW. We conclude that thermal convection would have played an important role as an energy source of dynamo action that generated a surface magnetic field for tens of millions of years in Vesta's early history.