We discuss major challenges in modeling giant impacts between planetary bodies, focusing
on the equations of state (EOS). During the giant impact stage of planet formation, rocky
planets are melted and partially vaporized. However, most EOS models fail to reproduce
experimental constraints on the thermodynamic properties of the major minerals over the
required phase space. Here, we present an updated version of the widely-used ANEOS
model that includes a user-defined heat capacity limit in the thermal free energy term. Our …