Date of Award

Summer 8-2025

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

First Committee Advisor

David Batuski

Second Committee Member

Neil Comins

Third Committee Member

James McClymer

Additional Committee Members

Liping Yu

Andre Khalil

Abstract

Core-collapse supernovae (CCSNe) represent the final stage in the life of massive stars, yet the conditions required to successfully launch an explosion remain an open question. In this work, I investigate the role of progenitor structure, rotation, and diagnostic explosion criteria using a suite of 1D simulations from both MESA and KEPLER stellar evolution models. I explore models from 18–20 Solar Masses with varying equatorial rotation rates—expressed either as a fraction of the ZAMS critical rate (MESA) or initial surface velocity (KEPLER)—and track their collapse through the GR1D code with neutrino heating.

A primary focus is placed on how pre-collapse features such as compactness, entropy gradients, and composition interfaces (notably the Si/Si-O boundary) correlate with explodability. To quantify this, I calculate a range of proposed explosion indicators. A diagnostic involving the advection-to-heating ratio is introduced to assess whether the ratio increases or declines in the final 100ms before falling below the explosion threshold, providing insight into marginal cases.

The results reveal a sharp division between MESA and KEPLER models, with rotation generally promoting explodability, though not uniformly. Models with shallow composition gradients and sustained heating dominance show stronger explosion signatures, while those with downward trends in the advection-to-heating timescale often fail despite crossing the canonical threshold. Comparative analysis emphasizes the sensitivity of CCSNe outcomes to progenitor structure, rotational configuration, and the choice of explosion metric.

This study provides a comprehensive pre- and post-bounce classification of explodability, highlights limitations of existing thresholds when applied in isolation, and lays groundwork for future studies spanning a broader progenitor mass range, with extensions to 2D simulations and observational comparisons.

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