Winds of Change: The Decisive Role of Mass Loss in the Evolution of Very Massive Stars

Massive and very massive stars are among the most influential objects in our Universe, being key agents in chemical enrichment, sources of ionizing photons, and representing progenitors of extreme explosions and exotic compact objects. Despite significant progress in our understanding of stellar structure and evolution over the past century, there remain open questions regarding the physical processes of very massive stars (above ∼ 100 M⊙) formation and evolution. The evolution of the most massive stars is a building block of modern astrophysics, shaping the evolution of the Universe, and so an accurate understanding and modeling is paramount. The goal of this thesis is to explore one of the major sources of uncertainties in very massive stars: their stellar winds. This thesis confronts this complex topic in two ways: First, I computed a comprehensive, foundational dataset of stellar models to be used as a resource for the astronomical community. They include full stellar tracks, nucleosynthetic yields, and ionizing photon counts for a wide range of initial masses and compositions. Second, I made a focused demonstration of how critically stellar fates depend on the subtle physics of VMS mass loss. I explored how modest, physically motivated adjustments to the mass loss prescriptions can dramatically alter their evolutionary path, thereby reshaping the predictions for their final fates and remnant mass spectrum. Ultimately, this research provides a more robust foundation upon which a more accurate and complete picture of the Universe may be built.