Edward M Sion is Professor in the Department of Astrophysics and Planetary Science at Villanova University and a leading expert in the field. He specializes on the structure and evolution of white dwarf stars and white dwarf stars in explosive binary star systems known as cataclysmic variables. His primary research interests include the formation and evolution of white dwarf stars, the physics and evolution of cataclysmic variable stars, and theoretical studies of accretion physics.