The internal composition of exoplanets is a key characteristic to understand their diversity and formation. The interior of small, Earth-like planets can be approximated as having a dense metallic core, a lower and upper silicate mantle, and a thin layer of ice or liquid water (Valencia, Sasselov & O’Connell 2007). The amount of elements such as iron (Fe), silicon (Si), or magnesium (Mg) plays an important role in influencing the extent of each of these layers (Sotin, Grasset & Mocquet 2007).
