Abundance Calculations of Neon Isotopes in the Predicted Lifetime of the Sun

Abstract

The elemental abundances of neon isotopes provide valuable insights into stellar evolution and nucleosynthesis. In this study, we calculate the abundances of the isotopes 18Ne, 19Ne, 20Ne, 21Ne, and 22Ne across the five principal evolutionary phases of the Sun: hydrogen burning, lively old age, onset of rapid growth and red giant, helium burning and helium exhaustion. The calculations were carried out using the open-source nucnet-tools package, developed by the Webnucleo Group at Clemson University. Initial isotope abundances were adopted from standard proto-solar compositions. Their evolution was computed under static hydrostatic burning conditions, assuming constant temperature and density within each phase. The results show that the stable isotopes 20Ne and 22Ne remain dominant throughout the Sun's lifetime, whereas the short-lived isotopes 18Ne and 19Ne decay rapidly during or shortly after the hydrogen-burning phase. The predictions obtained for the helium burning and exhaustion phases provide quantitative neon-isotope abundances that are not extensively reported in the existing literature. These results offer valuable reference values for future studies of solar and stellar evolution, nucleosynthetic pathways, and isotopic modeling.