The deaths of massive stars in binary systems

Core-collapse supernovae (ccSNe) are energetic explosions that mark the end of the life of massive stars, with initial masses above ~ 8 solar masses. These explosions shape their environments and produce many of the elements that are essential for life. Still, there are many unanswered questions about them and their stellar progenitors. Recent observations show that a significant fraction of massive stars are found in close binary systems and are expected to interact with a companion prior to explosion, exchanging mass or even merging. In this thesis we use population synthesis simulations to study the impact of binary evolution of the progenitors of ccSNe on the statistical properties of these explosions. We first focus on how binary interactions can extend the delay time between the formation of massive stars and their eventual explosions. We then present theoretical predictions about the stellar companions of hydrogen-poor ccSN progenitors at the moment of explosion, finding that in the majority of cases a quite unevolved companion is expected nearby. We use these results to interpret post-explosion observations of SN 2002ap and SN 1994I. We also study the properties of stars that become unbound from their binary systems due to a prior ccSN explosion from their companion. Finally, we find that 1/3 to 1/2 of hydrogen-rich ccSNe progenitors are expected to accrete mass from or merge with a companion prior to explosion. We investigate how these interactions may affect the core mass distribution of their progenitors.