Type Ia Supernovae (hereafter SNIa) play a crucial role in (Astro)physics. Their key contribution to distance measurement and cosmology was recognised with a Nobel Prize in Physics in 2011, and more recently in 2019 they were fundamental in re-opening the debate around the expansion of the Universe. In addition, SNIa are fundamental contributors to the chemical evolution of galaxies, being responsible for about 2/3 of the total iron-peak elements content in the Milky Way, about 1/3 of the so-called “alpha elements” (in particular Si, S, Ar, Ca, and Ti), and possibly to a significant portion of heavy trans-iron proton-rich isotopes called p-nuclei. Despite the importance of SNIa, we still do not know what stellar evolution path represents their dominant progenitor channel, being a matter of debate between different kinds of accreting carbonoxygen white dwarfs in binary systems (single-degenerate, hereafter SD, scenario) or white dwarfs merger events (double-degenerate, hereafter DD, scenario). Moreover, as light-curves, spectra and nucleosynthesis products are deeply impacted by the nature of the stellar system originating the explosion, large uncertainties are thus introduced when it comes to the actual use of SNIa as a tool, in particular in cosmology and chemical evolution of the Galaxy.
Several observables can be used to shed light on SNIa progenitors. Specific chemical abundances in our Galaxy, like manganese, are extremely sensitive to these progenitors, and are hence a unique tool to probe the origins of SNIa. Additionally, chemical analysis of meteorites, lightcurve measurements and gamma-ray spectroscopy provide a rich variety of astronomy to boost our understanding of SNIa progenitors. Investigation tools range from numerical models, astronomical observations and laboratory experiments, to the derivation of material compositions and nuclear reaction rates. The aim of this Specialist Discussion meeting, the second of a series started in November 2020, is to bring together researchers from all these different fields to promote interaction, networking and discuss strategies to progress our knowledge of these crucial astrophysical events.
Umberto Battino (Hull)
Brad Gibson (Hull)
Alexander Murphy (Edinburgh, FRAS)