ON VARIATIONS OF PRE-SUPERNOVA MODEL PROPERTIES

We explore the variation in single-star 15-30 M-circle dot, nonrotating, solar metallicity, pre-supernova MESA models that is due to changes in the number of isotopes in a fully coupled nuclear reaction network and adjustments in the mass resolution. Within this two-dimensional plane, we quantitatively detail the range of core masses at various stages of evolution, mass locations of the main nuclear burning shells, electron fraction profiles, mass fraction profiles, burning lifetimes, stellar lifetimes, and compactness parameter at core collapse for models with and without mass-loss. Up to carbon burning, we generally find that mass resolution has a larger impact on the variations than the number of isotopes, while the number of isotopes plays a more significant role in determining the span of the variations for neon, oxygen, and silicon burning. Choice of mass resolution dominates the variations in the structure of the intermediate convection zone and secondary convection zone during core and shell hydrogen burning, respectively, where we find that a minimum mass resolution of approximate to 0.01 M-circle dot is necessary to achieve convergence in the helium core mass at the approximate to 5% level. On the other hand, at the onset of core collapse, we find approximate to 30% variations in the central electron fraction and mass locations of the main nuclear burning shells, a minimum of approximate to 127 isotopes is needed to attain convergence of these values at the approximate to 10% level.