From Cool Supergiants to Cosmic Catastrophes: Red Supergiants and Supernova Mechanisms

Abstract

This thesis work employs multi-messenger astronomy to investigate the mechanisms driving massive star evolution and core-collapse supernovae. To these ends, I have cataloged and expanded the number of Galactic core-collapse supernovae progenitors and shown how the catalog significantly improves the astronomical community's ability to observe progenitors pre-explosion and during the early phases of core collapse. This approach goes beyond traditional multi-wavelength observations of circumstellar material by incorporating direct detections of neutrinos and gravitational waves, which provide unique insight into the internal dynamics of supernova explosions. While neutrinos are currently the leading candidates for powering the outward shock of a core-collapse supernova, theoretical models have yet to reach convergence. This challenge highlights a fundamental issue: if we cannot accurately model the evolution of supernova progenitors up to the point of collapse, it is difficult to achieve consistency in our neutrino-driven explosion models. The diversity of possible evolutionary pathways, uncertainties surrounding the dominant mass-loss mechanisms, and the complex influence of mass, metallicity, and multiplicity make the final red supergiant phases before collapse particularly compelling. To address these open questions, I discuss the results from attempts to probe the internal dynamics of massive stars—including the effects of binarity and dust formation—while also seeking to overcome observational limitations. From this, this thesis lays out a quantified approach to how our limited knowledge of red supergiant mass loss drastically impacts our ability to estimate SN progenitor characteristics and their implications for stellar evolution. I have found that the explanation comes from inaccurate dust models. I have further found observational support, based on a significant sample with well-understood biases, confirming an evolutionary change in the primary driver of mass loss during the red supergiant phase and linking the influence of both metallicity and mass. Observations of galaxies at high redshift (z>6) reveal substantial dust reservoirs. Yet, the timescales required for conventional dust production channels are likely too long to account for these early abundances. These unexpectedly large quantities of cold dust have renewed interest in sources and evolutionary pathways of early cosmic dust. However, despite long-standing predictions that core-collapse supernovae are major contributors to this cosmic dust, significant discrepancies persist between theoretical dust yields and observational estimates, as well as in the inferred survival efficiency of dust grains. From late-time James Webb Space Telescope Mid-Infrared Instrument imaging and additional archival data, I was able to analyze the evolution of the dust and place constraints on the source of heating and origins of the dust seen in SN1996cr. These late-time observations highlight the value of long-term monitoring of supernovae regarding both their supernova progenitors and physics.