Theoretical evidence of H-He demixing under Jupiter and Saturn conditions

Abstract

The immiscibility of hydrogen-helium mixture under the temperature and pressure conditions of planetary interiors is crucial for understanding the structures of gas giant planets (e.g., Jupiter and Saturn). While the experimental probe at such extreme conditions is challenging, theoretical simulation is heavily relied in an effort to unravel the mixing behavior of hydrogen and helium. Here we develop a method via a machine learning accelerated molecular dynamics simulation to quantify the physical separation of hydrogen and helium under the conditions of planetary interiors. The immiscibility line achieved with the developed method yields substantially higher demixing temperatures at pressure above 1.5 Mbar than earlier theoretical data, but matches better to the experimental estimate. Our results suggest a possibility that H-He demixing takes place in a large fraction of the interior radii of Jupiter and Saturn, i.e., 27.5% in Jupiter and 48.3% in Saturn. This indication of an H-He immiscible layer hints at the formation of helium rain and offers a potential explanation for the decrease of helium in the atmospheres of Jupiter and Saturn.

3 figures, accepted in Nature Communications

References in corpus (8)

• The Phase Diagram of a Deep Potential Water Model
• Phase separation in hydrogen-helium mixtures at Mbar pressures
• Homogeneous nucleation of ice
• Evidence for a Dichotomy in the Interior Structures of Jupiter and Saturn from Helium Phase Separation
• Bayesian Evolution Models for Jupiter with Helium Rain and Double-diffusive Convection
• Theoretical evidence of H-He demixing under Jupiter and Saturn conditions
• Towards the same line of liquid-liquid phase transition of dense hydrogen from various theoretical predictions
• The Interiors of Jupiter and Saturn

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• The Evolution and Internal Structure of Neptunes and Sub-Neptunes: The importance of thermal conductivity in non-convective regions
• First-principles simulation of shocked H-He mixture along the principal Hugoniot
• Deformation mechanisms and compressive response of NbTaTiZr alloy via machine learning potentials