Which Planets Have an Atmosphere? Radiation vs. Escape Velocity

All other things being equal, more massive planets that receive less high-energy radiation from their stars are more likely to have atmospheres than smaller planets that receive more radiation. But how strong is this relationship across the galaxy? Is there a line on this graph that separates exoplanets with and without atmospheres (a so-called “cosmic shoreline”)? Can we accurately predict whether an exoplanet has an atmosphere based only on its gravity and the amount of high-energy light it receives from its star, or are there too many other variables to consider? Webb and Hubble are observing rocky exoplanets and their red dwarf host stars to help answer these questions.