Lecturer:  Prof. Selma de Mink, director at the Max Planck for Astrophysics (MPA)
Abstract:

The first direct detection of Gravitational Waves brought great excitement among physicists and astrophysicists alike.  Especially the high masses, about 30 times that of the sun, were unexpected, being well above any of the stellar-mass black holes known in X-ray binaries. To date, we have 90 significant detections with published parameters.  In this Lecture, I will invite you to relive some of the excitement felt by stellar astrophysicists. For us, the neutron stars and black holes responsible for the detections are the fossils of very massive stars, that are still poorly understood.  These massive stars nearly always come in binary systems. They are rare and live short-lived, yet they played a disproportionate role in transforming the pristine Universe left after the Big Bang into the modern Universe as it is today.  — In this lecture, I will discuss what gravitational wave detections teach us about massive stars' lives and fates.  I will touch on the main formation scenarios and emphasize for an alternate pathway through chemically homogeneous evolution. I will further discuss the deep significance of pair-instability supernovae and the prospect that we may learn about nuclear physics or sources that are not of stellar origin.