host: Davide Gerosa
Title: Life and death of the most massive stars: mapping the uncertain formation of massive black holes and gravitational-wave sources
Abstract: The formation of massive black holes and gravitational-wave sources depends heavily on our understanding of massive star evolution. However, our current theoretical frameworks are full of uncertainties, leading to a wide spread in the predicted populations. This problem is especially true for very massive stars. Rather than just being heavier versions of standard black hole progenitors, very massive stars are a completely new class of objects driven by different underlying physics. In this seminar, we will map how these massive and very massive stars live and die. We will look at how stellar expansion, the formation of convective envelopes, and binary dynamics impact the survival of binary systems and the formation of gravitational wave sources. We will also discuss the major role of stellar winds, showing how different mass-loss models can completely change the predicted black hole mass distribution and the structural evolution of these stars. Ultimately, this talk will show that while stellar expansion is key to creating observable gravitational wave sources by initiating mass transfer events, very massive stars, due to their strong ejections of mass, rarely expand enough to lead their host binaries towards this evolutionary channel. Because of these complex differences, we must compare multiple evolutionary codes rather than trusting a single model at face value