Scorching lava planets can maintain thick gaseous envelopes while cooler rocky worlds lose their air entirely. Astronomers long assumed that ferocious stellar radiation stripped atmospheres from hot worlds first while leaving cooler planets intact. Instead, persistent oceans of molten rock trap volatile gases deep inside liquid mantle layers and release them slowly over billions of years.
On extremely hot planets, orbital gravity generates intense tidal heating that keeps the planetary surface liquefied. This persistent magma ocean functions like a deep reservoir, dissolving atmospheric gases directly into molten silicate rock. As stellar radiation blows away the thin upper atmosphere, the churning lava continuously outgasses fresh vapors to replace the lost air. Cooler rocky worlds freeze solid instead, trapping gases deep underground while the remaining surface air is stripped away.
Researchers analyzed telescope observations from the James Webb Space Telescope using a coupled evolution model of planetary atmospheres and interiors. They tracked how atmospheric escape and interior outgassing balance across G, K, and M dwarf stellar systems over time. The simulations revealed an airless valley separating hot gas-shielded sandbars from cooler rocky planets.
This dual-boundary framework allows astronomers to predict which close-in exoplanets retain atmospheres based on stellar type, planet mass, and tidal heating. Observers can now refine telescope targets for atmospheric searches across systems like TRAPPIST-1 and directed James Webb Space Telescope surveys.