Extent of iron oxidation during super-Earth core formation

Ascertain how much metallic iron is oxidized to FeO during core formation in super-Earths as a function of bulk water mass fraction and the extreme pressure–temperature conditions characteristic of their differentiation, to quantify its impact on core size and planetary radii.

Background

The authors evaluate the potential for water to oxidize metallic iron, which would transfer iron into the mantle as FeO and alter core mass and radius predictions. While they show that modest oxidation likely has a small effect on planetary radii, the actual fraction of iron oxidized under super-Earth core formation conditions is not constrained.

To explore sensitivity, the paper varies the fraction of iron in the mantle as FeO, but emphasizes that the true degree of oxidation at relevant pressures and temperatures remains unknown.