ASTRONOMY COLLOQUIUM

An improved understanding of the lifecycle of massive stars benefits every subfield in astrophysics. Through their ionizing radiation, powerful stellar winds, nucleosynthesis, and deaths as supernova (SN) explosions, massive stars give birth to black holes and neutron stars, while stoking the dynamical and chemical evolution of the universe. Although the study of massive stars is one of the oldest subfields in astronomy, the recent advent of wide-field time-domain surveys has launched an upheaval in the field of stellar evolution. By opening new regimes of the dynamic sky, we have uncovered new types of astronomical transients, challenging our views of the physical processes that occur during the lives—and deaths—of massive stars. Our understanding of the types of stars that explode as supernova have been particularly impacted: new data has revealed supernova progenitors that we did not expect, a lack of progenitors that were anticipated, and pointed to classes of stars that we have not yet observed. In this talk I will highlight on-going efforts to constrain the evolution and ultimate fate of massive stars, using observations of both transient phenomena and resolved massive star populations in local group galaxies.