碳氮氧循環
A better approximation is to take "ε" = "L"/"M", the energy generation rate per unit mass, as "ε" is proportional to "TI"15, where "TI" is the core temperature. This is suitable for stars at least as massive as the Sun, exhibiting the CNO cycle, and gives the better fit "R" ∝ "M"0.78.