The research goal of this work is to detect and characterize very low mass white dwarfs in binary systems, in order to help understand likely Type Ia supernovae progenitors. About 30-50 new systems will be identified and studied with a new census of extremely low-mass white dwarfs identified using the Sloan Digital Sky Survey and the Hyper-Velocity Star Survey. This work will provide critical new insights into the formation and fate of exotic low-mass white dwarfs. It will also give us new tests of General Relativity and tidal evolution in short-period systems.
Understanding the constituents and history of the cosmos lies at the heart of modern astrophysics. In the last 15 years, observations of Type Ia supernovae (SNe) indicate that the expansion of the universe is dominated by dark energy. Until we find the progenitors, it is impossible to understand the systematic uncertainties and to optimize SNe Ia to definitively explore cosmology. The SNe Ia progenitor problem is therefore a key problem in astronomy today, and this research promises to add significant knowledge to our understanding of these exotic systems. The work also has a broad plan for undergraduate, graduate, and postdoctoral involvement in the observations, data analysis, and dissemination of results.