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Updated: Jun 26, 2026
05:46
High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems
Published on: January 24, 2014
Phase separation in hydrogen-helium mixtures at Mbar pressures
Miguel A Morales1, Eric Schwegler, David Ceperley
1Department of Physics, National Center of Supercomputing Applications, and Institute of Condensed Matter Theory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Summary
Helium is partially miscible in Saturn and Jupiter interiors. Calculations show helium and hydrogen demixing temperatures are high enough to impact planetary evolution models.
Area of Science:
- Planetary Science
- Computational Physics
- Materials Science
Background:
- Understanding the interior structure of gas giants like Jupiter and Saturn is crucial for planetary science.
- Hydrogen-helium mixtures under extreme pressures and temperatures are key components of these planetary interiors.
Purpose of the Study:
- To calculate the properties of hydrogen-helium mixtures at Mbar pressures and 4000-10000 K.
- To determine the conditions under which helium becomes insoluble in metallic hydrogen.
- To assess the implications for the interior structure and evolution of Jovian planets.
Main Methods:
- First-principles molecular dynamics simulations were employed.
- Equation of state was determined as a function of density, temperature, and composition.
- Thermodynamic integration was used to estimate the Gibbs free energy of mixing.
Main Results:
- The equation of state for hydrogen-helium mixtures was calculated.
- Demixing temperatures for helium and hydrogen were determined.
- Helium is found to be partially miscible in Saturn's interior at pressures around 5 Mbar, and to a lesser extent in Jupiter.
Conclusions:
- Helium remains partially miscible in significant portions of Saturn's interior.
- The calculated demixing temperatures have direct relevance to models of Jovian planet interiors.
- These findings refine our understanding of the internal dynamics and evolution of gas giants.
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