MAGRATHEA: an open-source spherical symmetric planet interior structure code

Abstract

MAGRATHEA is an open-source planet structure code that considers the case of fully differentiated spherically symmetric interiors. Given the mass of each layer, the code iterates the hydrostatic equations in order to shoot for the correct planet radius. The density may be discontinuous at a layer's boundary whose location is unknown. Therefore, in our case, shooting methods, which do not require predefined grid points, are preferred over relaxation methods in solving the two-point boundary value problem. The first version of MAGRATHEA supports a maximum of four layers of iron, silicates, water, and ideal gas. The user has many options for the phase diagram and equation of state in each layer and we document how to change/add additional equations of state. In this work, we present MA-GRATHEA capabilities and discuss its applications. We encourage the community to participate in the development of MAGRATHEA at https://github.com/Huang-CL/Magrathea.