The Progenitors of Type Ia Supernovae
Benjamin Shappee

Despite the fact that Type Ia Supernovae (SNe Ia) were used to discover the accelerating universe, the physical nature of their progenitor systems remains theoretically ambiguous and observationally elusive. It is commonly accepted that SNe Ia result from the thermonuclear explosion of a carbon-oxygen white dwarf in a close binary system, but the nature of the binary companion and the sequence of events leading to the SN explosion are still uncertain. There are two dominant models: the double-degenerate scenario where the progenitor system contains two white dwarfs, and the single-degenerate scenario where the companion is a main-sequence, subgiant, red-giant, or helium star. The search for observational signatures capable of distinguishing between these two models has proven challenging. However, in recent years, significant strides have been made to observationally constrain the progenitor systems. I will cover these advancements in detail, and place them in the context of our evolving picture of SNe Ia.