SENSITIVITY TO TEMPERATURE OF NUCLEAR-ENERGY GENERATION BY HYDROGEN BURNING

The sensitivity to temperature of nuclear energy generation by hydrogen burning is discussed. The complexity of the sensitivity is due to the different equilibration time-scales of the constituents of the p—p chain and CN cycle and the dependence of their abundances and time-scales on temperature. The time-scale of the temperature perturbation, compared to the equilibrium time-scale of a constituent, determines whether the constituent is in equilibrium and affects the sensitivity. The temperature sensitivity of the p—p chain for different values of hydrogen abundance, when different constituents come into equilibrium is presented, as well as its variation with 3He abundance. The temperature sensitivity is drastically different from nn, the temperature sensitivity of the proton—proton reaction, unless the time-scale of temperature perturbation is long enough for 3He to remain in equilibrium. Even in this case the sensitivity of the p—p chain differs significantly from nll9 unless the temperature is so low that PPH and PP III chains can be neglected. © Royal Astronomical Society.