A Detailed Model Grid for Solid Planets from 0.1 through 100 Earth Masses

Abstract

ABSTRACTThis article describes a new grid for the mass–radius relation of three-layer exoplanets within the mass range of 0.1–100 M⊕. The three layers are: Fe (!ϵ-phase of iron), MgSiO3 (including both the perovskite phase, post-perovskite phase, and its dissociation at ultrahigh pressures), and H2O (including Ices Ih, III, V, VI, VII, X, and the superionic phase along the melting curve). We discuss the current state of knowledge about the equations of state (EOS) that influence these calculations and the improvements used in the new grid. For the two-layer model, we demonstrate the utility of contours on the mass–radius diagrams. Given the mass and radius input, these contours can be used to quickly determine the important physical properties of a planet including its ! p0 (central pressure), ! p1/p0 (core–mantle boundary pressure over central pressure), CMF (core mass fraction) or CRF (core radius fraction). For the three-layer model, a curve segment on the ternary diagram represents all possible relative mass proportions of the three layers for a given mass–radius input. These ternary diagrams are tabulated with the intent to make comparison to observations easier. How the presence of Fe in the mantle affects the mass–radius relations is also discussed in a separate section. A dynamic and interactive tool to characterize and illustrate the interior structure of exoplanets built upon models in this article is available online.