Hydrogen, Helium Separation May Explain Saturn Radiation

摘要

Jovian planets radiate more energy than they absorb from the sun. In the case of Saturn, researchers suspect that the source of a large fraction of the extra energy may be the phase separa-rntion of helium and hydrogen at the high temperatures and pressures found in the planetary interior. Miguel Morales et al. conducted computer simulations of the molecular dynamics of hydrogen and helium from first principles and find that condensing helium releases latent heat and dissipates energy as droplets fall toward the planet's core. Under high pressure, hydrogen becomes metallic; helium, too, ionizes and becomes metallic, which would increase its solubility in hydrogen, but the authors find that the molecular mixing would already have occurred at a lower temperature than that at which metallization takes place. Phase separation of hydrogen and helium may help to reconcile current evolution models for Saturn with observational data, the authors say.