Atmosphericescapeisakeyprocesscontrollingthelongtermevolutionofplanets.Radiativecoolingcompetesforenergyagainstatmosphericescapeinplanetaryupperatmospheres.Inthiswork,weuseapopulationbalancemethodandaMonteCarlomodeltocalculatethepreviouslyignoredemissionsofmetals(C,N,Oandtheirions)andcomparethemwithradiativerecombinationofHIIandLy-αemissionofHI,whicharethemostefficientcoolingmechanismscurrentlyrecognizedintheupperatmospheresofhotJupiters.TheresultsshowthattheemissionsofC,N,Oandtheirionsarestrongnon-linearfunctionsofenvironmentalparameters(temperature,density,etc.)andarelikelytobeefficientcoolingmechanismsintheupperatmospheresofclose-inexoplanets.
