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Center for Nonlinear Studies |
Type Ia supernovae have been the subject of intense study for decades, spurred in part by their important contribution to our understanding of dark energy, but the identity of their progenitors has remained a mystery. However, a coherent and satisfying explanation may finally be within reach. In this talk, I will present the mounting evidence that most Type Ia supernovae are explosions of sub-Chandrasekhar-mass white dwarfs (WDs) in double WD binaries, in stark contrast to the classical picture of a Chandrasekhar-mass WD accreting from a non-electron-degenerate companion. This evidence includes progenitor modeling, explosion simulations, and radiative transfer calculations that match observations with higher and higher fidelity; the prediction and discovery of an increasing number of hypervelocity surviving companion WDs; and recent theoretical work showing that nearly all WDs can support detonations if impacted with sufficient strength. I will also describe the new and intriguing possibility that most Type Ia supernovae actually arise from the detonations of not just one, but both, of the sub-Chandrasekhar-mass WDs in double WD binaries.
Bio: Ken Shen is a staff researcher in the UC Berkeley Department of Astronomy. He received his PhD in 2010 from UC Santa Barbara, advised by Lars Bildsten, and was an Einstein fellow and postdoctoral scholar from 2010-2014 at UC Berkeley. He primarily studies thermonuclear explosions in interacting binary stellar systems, using tools ranging from pen-and-paper calculations to running 1D stellar evolution and multi-D reactive hydrodynamics and radiation transport codes.
Host: swj@lanl.gov