Our sun. III. Present and future

Abstract

Self-consistent evolutionary models were computed for the Sun, starting with contraction on the Hayashi track and using Los Alamos interior opacities and Sharp molecular opacities. The models are calibrated to match the observed present solar luminosity, radius and Z/X at the solar age. The resulting presolar Y and Z are 0.274 and 0.01954, respectively. The predicted present solar neutrino capture rates are 6.53 and 123 SNU for ³⁷Cl and ⁷¹Ga, respectively. The model follows the Sun through its evolution to a white dwarf, passing through a red giant branch (RGB) phase with a maximum luminosity of 2300 L⊙ and a radius of 170 R⊙ and an asymptotic giant branch (AGB) phase with four thermal pulses, during which a maximum luminosity of 5200 L⊙ and a maximum radius of 213 R⊙ are attained. The preferred mass-loss rate on the RGB and AGB is a Reimers wind with a mass-loss parameter η = 0.6, normalized from inferred mass loss in globular cluster stars. The Sun is predicted to spend 11 Gyr on the main sequence, 0.7 Gyr cooling toward the RGB, 0.6 Gyr ascending the RGB, 0.1 Gyr on the horizontal branch, 0.02 Gyr on the early AGB, 0.0004 Gyr on the thermally pulsing AGB and 0.0001 Gyr on the traverse to the planetary nebula stage. – AI-generated abstract.