Mapping out the parameter space for photoevaporation and core-powered mass-loss

Abstract

Understanding atmospheric escape in close-in exoplanets is critical to interpreting their evolution. We map out the parameter space over which photoevaporation and core-powered mass-loss dominate atmospheric escape. Generally, the transition between the two regimes is determined by the location of the Bondi radius (i.e. the sonic point of core-powered outflow) relative to the penetration depth of extreme ultra-violet (XUV) photons. Photoevaporation dominates the loss when the XUV penetration depth lies inside the Bondi radius (RXUV