STUDY OF ASTROPHYSICAL NUCLEAR REACTIONS AND THEIR ROLE IN STELLAR EVOLUTION

Abstract

Astrophysical nuclear reactions are fundamental to the life cycle of stars and the chemical evolution of the universe. This study investigates the critical nuclear processes occurring within stellar environments, including the proton-proton chain, the CNO cycle, the triple-alpha process, and neutron-capture mechanisms, to understand how they govern stellar structure, energy generation, and nucleosynthesis. Using a mixed-methods approach combining observational data, computational simulations, and sensitivity analyses, we evaluated reaction rates, cross-sections, and temperature dependencies under varying stellar conditions. The results reveal distinct differences in reaction pathways based on stellar mass, metallicity, and evolutionary phase, confirming the predictive capacity of current theoretical models while highlighting areas requiring refined measurements. In particular, the role of neutron star mergers and core-collapse supernovae in producing heavy elements beyond iron is strongly supported by our simulations. The use of updated reaction rate libraries like STARLIB has significantly improved the accuracy of elemental abundance predictions. Moreover, the integration of quantum tunneling effects and reaction rate uncertainties provides enhanced reliability in nucleosynthesis modeling. This study not only reinforces existing frameworks of stellar evolution but also contributes to the ongoing efforts in galactic archaeology, stellar age estimation, and cosmochemical modeling. The findings have implications for refining stellar evolution codes and advancing nuclear astrophysics research, particularly in understanding the origins of heavy elements and the formation history of galaxies.