Abstract

At a late stage of its accretion, the Earth experienced high-energy planetary impacts. Following each collision, the metal core of the impactor sank as millimetric drops into a molten silicate magma ocean — the so-called “iron rain”. The efficiency of chemical equilibration between metal and silicates controlled the initial temperature and composition of the Earth. Current parameterizations of the equilibration efficiency neglect the influence of planetary rotation after impact.

In a different planetary context, the icy moon Ganymede sustains an intrinsic magnetic field, likely generated by fluid motions in its iron-rich liquid core. Core evolution models suggest solidification proceeds from the outer boundary inward, producing dense, pure iron crystals that sink and remelt at greater depth. This process, referred to as “iron snow”, is thought to drive core dynamics that feed the magnetic field. Yet, it is commonly modeled as purely fluid convection, neglecting the presence and properties of solid particles.