Core–envelope miscibility in sub-Neptunes and super-Earths

Abstract Sub-Neptunes and super-Earths, the most abundant types of planet in the galaxy, are unlike anything in the Solar System, with radii between those of Earth and Neptune 1,2 . Fundamental questions remain regarding their structure and origin. Although super-Earths have a rocky composition 3 , sub-Neptunes form a distinct population at larger radii and are thought to consist of a rocky core overlain by a hydrogen-rich envelope 4,5 . At the extreme conditions of the core–envelope interface (exceeding several gigapascals and several thousand kelvin 4,6 ), reaction between core and envelope seems possible, but the nature and extent of these reactions are unknown. Here we use first-principles molecular…

• NS
  National Science Foundation

  Award: 2223935
• NA
  National Aeronautics and Space Administration
• NS
  Nuclear Safety and Security Commission
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  Institute for Digital Research and Education, University of California, Los Angeles