A STUDY OF SOLAR EVOLUTION

Abstract

Evolutionary sequences of solar models have been calculated using the Henyey method of model construction. These sequences were started at the threshold of stability, at which the released gravitational potential energy of the sun is just sufficient to supply the thermal, dissociation, and ionization energies of the model. It was found that the present solar characteristics were closely reproduced when a mixing length equal to two pressure scale heights was used in the convection theory, and when a solar initial helium abundance, based on solar cosmic-ray measurements, was chosen. The sun was again found to have a high luminosity during its contraction phase and to approach the main sequence in only a few million years. Tables of selected characteristics of some of the models are presented.