  Gas giants are believed to form by the accretion of hydrogen-helium gas
around an initial protocore of rock and ice. The question of whether the rocky
parts of the core dissolve into the fluid H-He layers following formation has
significant implications for planetary structure and evolution. Here we use ab
initio calculations to study rock solubility in fluid hydrogen, choosing MgO as
a representative example of planetary rocky materials, and find MgO to be
highly soluble in H for temperatures in excess of approximately 10000 K,
implying significant redistribution of rocky core material in Jupiter and
larger exoplanets.
