Abundances in Astrophysical Environments: Reaction Network Simulations with Reaction Rates from Many-nucleon Modeling

We use the ab initio (first-principle) symmetry-adapted no-core shell model (SA-NCSM) to calculate reaction rates of significance to type I X-ray burst nucleosynthesis. We consider the $^{\mathrm{18}}$O(p,$\gamma )^{\mathrm{19}}$F reaction, which may influence the production of fluorine, as well as the $^{\mathrm{16}}$O($\alpha $,$\gamma )^{\mathrm{20}}$Ne reaction, which is key to understanding the production of heavier elements in the universe. Results are compared to those obtained in the no-core sympletic shell model (NCSpM) with a schematic interaction. We discuss how these reaction rates affect the relevant elemental abundances.