End‐Member Venusian Core Scenarios: Does Venus Have an Inner Core?

Abstract

AbstractVenus's lack of a magnetic field suggests it may not have an inner core; however, evidence of Venus's internal density structure has historically been limited by its slow rotation. New moment of inertia (MoI) estimates allow us to constrain its internal density and thermal structure. Here, we use a mineral‐physics solver, and incorporate equations of state for silicate mantle minerals and core phases, to calculate radial density profiles for variable core and mantle compositions, and estimate the MoI and planetary mass, and optimal outer and inner core radii. For Earth‐like core compositions, our best fit radius for Venus's core is 3,147.1 ± 16.8 km, with no inner core—implying the liquid core has not cooled sufficiently to start crystallizing. However, for enriched light‐element concentrations in the core (>∼11 wt%), solutions fit large, light cores (∼4,000 km), and large inner cores (>∼2,000 km), underpinning the need for tighter cosmochemical/geophysical constraints on these endmembers.