Hydrogen-to-helium ratio under helium depletion
= Hydrogen-to-helium ratio under helium depletion
Removing <helium> from a hydrogen-rich envelope lowers He/H and raises its reciprocal H/He. A helium-rain explanation of atmospheric depletion must keep those two ratio conventions distinct. Settling helium-rich material can release <gravitational energy> while changing atmospheric composition; excess <luminosity> alone does not uniquely determine the interior process.