Study: Many mini‑Neptunes may have solid surfaces ^{CEFR A2}

Mini‑Neptunes are planets a little smaller than Neptune. They have a mix of rock and metal and thick atmospheres of hydrogen, helium and maybe water. Astronomers find many of these planets around other stars, but none in our solar system.

A team led by Professor Eliza Kempton at the University of Chicago used observations and computer models to study their surfaces. New data from the James Webb Space Telescope of GJ 1214 b suggest its atmosphere may contain larger molecules. The researchers found that heavier, hot atmospheres can create very high pressure at the surface. This pressure can compress molten rock back into a solid, so many planets thought to be lava worlds may have solid surfaces instead.