Astronomy Colloquium

Despite the wide-ranging role Type Ia supernovae (SNe Ia) play throughout astrophysics, we lack a firm theoretical understanding of how they arise.  For decades, the "single-degenerate" scenario, in which an accreting white dwarf reaches the Chandrasekhar mass, held sway.  However, spurred by recent observational and theoretical advances, researchers have begun exploring alternative progenitor channels.  In this talk, I will show why some of us were drawn to the "dynamically driven double-degenerate double-detonation" (D6) scenario, and how it makes unique predictions for surviving hypervelocity companions that were confirmed by the Gaia satellite earlier this year.  These stars, perhaps the fastest unbound stars in the Milky Way, represent the first ever detections of SN Ia survivors and have brought the D6 scenario to the forefront of the field as the only known SN Ia progenitor scenario to succeed in nature.