Influence of heavy elements on the properties of H-He dense plasma mixtures in giant planet envelopes

Hydrogen and helium are by far the dominant species in gaseous giant planet interiors. It is also certain that heavier elements must be present, up to a few percents in number. The influence of these heavy elements on the properties of H-He mixtures is however unknown and so is their distribution throughout the envelope, although they must influence the density profile in the envelope and can inhibit a large-scale convection. In order to investigate the properties of H-He dense plasma mixtures enriched in heavy elements, we performed molecular dynamics coupled to density functional theory of several mixtures on a wide range of temperature and pressure. We studied the influence of different elements on the equation of state, the chemistry and the transport properties of giant planet H-He envelopes. We also studied their effect on predicted structure for giant planets.