| Crynodeb: | <p>In this thesis we examine several improvements which can be made to the canonical under- standing of Galactic Chemical Evolution (GCE) models in light of modern developments in stellar physics and new modelling techniques. Not only is GCE a vital component of our understanding of the history and composition of the universe in its own right, but since it incorporates physics on the scale of the cosmological to the subatomic, it may also be used as an independent probe and constraint on physics across many different fields.</p>
<p>We develop two brand new, state-of-the-art models for studying galactic chemical evo- lution under two differing paradigms: the Simple Analytical Chemical Evolution Model (sacem) which allows for rapid and complete scans of the high-dimensional parameter space associated with GCE, and the updated version of the Radial Migration in Chemical Evolution Simulation (RAMICES II), which emulates the underlying physics chemical evolution as faithfully, and completely, as possible.</p>
<p>These models allow us to investigate the origin of r-process nucleosynthesis within the Milky Way, in particular, identifying the ability of 'collapsar' events to contribute meaningfully to the global r-process budget. Utilising the sacem code, we are able to evaluate in excess of 10<sup>12</sup> potential models of the galaxy, and evaluate them against intentionally weak constrains on the resulting chemical and temporal properties, and hence provide a strong upper bound on the ability of such events to contribute to the r-process abundance of the Milky Way at late times.</p>
<p>We study the impact of advances in stellar evolution modelling on GCE models, utilising new rotationally-resolved stellar evolution codes and nucleosynthetic yield grids. We show that the output from these new stellar models is fundamentally irreconcilable with observed data, and hence develop a number of tools which allow future stellar modelling to be rapidly diagnosed as incompatible, providing a new constraint on the internal evolution of stellar bodies.</p>
<p>Finally, we apply our new RAMICES II model to briefly study the phenomena of metallicity- offset, strongly peaked curves in the gas-phase abundance diagrams – so called 'caustics' – and how these imprint themselves in non-trivial ways on the stellar abundance plane, using them to inform future studies of both r-process nucleosynthesis and the assembly history of the galaxy.</p>
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