The stellar binary progenitors of interacting supernovae

Massive stars, with initial masses above ~8M⊙, typically end their lives in supernova explosions, which shape the evolution of their host galaxies and form compact remnants such as neutron stars or black holes. Because massive stars often have companions, their compact remnants may later merge, producing gravitational waves. Although our understanding of massive star evolution has improved greatly in recent decades, some phenomena still challenge our models. In particular, the growing evidence for supernovae whose massive progenitors were enshrouded in circumstellar material indicates that some massive stars lose far more mass in their late evolutionary stages than expected. The literature has so far mainly focused on single-star mechanisms to produce circumstellar material in a timely fashion, inspired by the observations of bright outbursts preceding some supernovae. However, the presence of a binary companion also provides a natural way to produce circumstellar material by triggering mass transfer shortly before the explosion, in which any material not accreted by the companion is expelled by the system. In this thesis, we study how binary evolution contributes to the number of supernovae which would interact with circumstellar matter, as well as their features. To this end, we first calculated a series of binary evolution models to discuss H-rich and H-poor interacting supernovae. We found that binary-induced mass-loss can produce massive circumstellar matter that, when swept by the supernova ejecta, releases significant energy, compatible with that observed in Type IIn, Type Ibn, Type Icn, and even SLSNe-II. Using a previously computed comprehensive large-scale gird of detailed binary evolution models, we developed a population-synthesis code to make predictions on the number of transients affected by the presence of circumstellar material. We find that our predictions roughly match the observed number of Type IIn and Type Ibn supernovae. Although our results suggest that mass-loss due to a binary companion could contribute significantly to the population of interacting supernovae, this does not dismiss the other single-star theories proposed in the literature. Rather, the binary channel may ultimately run concurrently with, or even help trigger, the single-star mechanisms otherwise suggested. We also turned our attention to those supernovae where, right after the explosion, the newly-born compact object interacts periodically with the binary companion, which is thought to be at the origin of the light curve undulations observed in SN2022jli. Our results suggest that this interaction process may actually affect a non-negligible fraction of H-poor supernovae and offer testable predictions for the features of their companions, especially in the case of SN2022jli. This study warrants re-examination of archival supernovae, and the future concurrent observations of multiple all-sky facilities may help detect more such events.