Date of Award

5-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

Committee Chair/Advisor

Bradley S. Meyer

Committee Member

Marco Ajello

Committee Member

Mark D. Leising

Committee Member

Jens Oberheide

Abstract

Nucleosynthesis is the collection of processes that are responsible for the vast diversity of nuclear species seen in nature. Computational models are upbiquitous throughout the field of astrophysics and are used to attempt to reproduce the observed abundances of these nuclear species. Though these models can be quite robust, we find a lack in the field highlighting the importance of reaction rates to how the final abundances are obtained. These various reaction rates critically dictate the reaction pathways that contribute to the final abundances, and these pathways are highly dependent on the nuclear reaction rates themselves. Rather than focus on the final abundances given by a computational model, we give a simple mathematical approach to the study of these pathways for nucleosynthetic processes that can be modeled as directed acyclic graphs. We show that the individual path approach can be summed over the paths to find the total contribution to the final species abundances. Furthermore, we show how a change in reaction rate varies the paths and the respective dominance of the paths amongst themselves. This approach can then be used to identify reactions that significantly alter the paths and the associated final abundances, which would be of interest for the astrophysics and nuclear physics communities.

Available for download on Wednesday, April 12, 2023

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