A lower limit to energy evolution in stellar matter

Abstract

It is well recognized that the energy generation in stellar interiors is due to nuclear reactions in which protons play a dominant part. This circumstance fixes, as is shown here, for stellar material of given density and chemical constitution a lower limit to the rate of energy-generation-the limiting value increasing very rapidly as the density of the material and the proportion of hydrogen in it increases. In the present note we shall only consider the reaction leading to the formation of deuteron by proton combination (H + H = D + ε^plus), though the results discussed here can easily be extended to other nuclear transformations brought about by protons. The probability of this astrophysically important reaction has been recently calculated by Bethe and Critchfield¹, who conclude that for stars lighter than the sun this process is the main source of energy.