EAS Doctoral Proposal Defense by Vrutant Vikasbhai Mehta
Abstract:
Type Ia supernovae (SNe Ia) are common luminous astrophysical transients. SNe Ia are thought to originate from the thermonuclear runaway of a mass accreting white dwarf (WD) in binary systems. While SNe Ia have demonstrated their importance in measuring the expansion rate of the universe and the chemical evolution of galaxies, key questions about their progenitors and explosion mechanisms are still open. In recent years, the helium-ignited binary WD merger has emerged as a robust channel leading to normal SNe Ia. In this channel, two unequal mass WDs with thin surface helium layers begin mass transfer (accretion) from the lower mass (secondary) WD onto the higher mass (primary) WD. During this accretion, the surface helium layer detonation on the primary can trigger another detonation near its core, which leads to complete disruption of the primary WD. The secondary WD is impacted by the ejected material and potentially also triggers helium and core detonations.
This Ph.D. thesis aims to investigate the end-to-end evolution of the helium-ignited binary WD merger channel–from the generation of physically consistent initial conditions of the binary systems to the supernova remnant phase of the ejecta. We will employ the FLASH-X hydrodynamical simulation framework to capture the full 3D evolution of the binary WD system. For accurate modeling of these systems, our ongoing efforts focus on improving the existing gravity solvers by implementing flux-conservative numerical approaches for angular momentum and total energy conservation in the framework of FLASH-X. With these new developments, the resulting models will be post-processed with radiation transport codes (SuperNu, Sedona) to generate synthetic spectra. The systematic comparison between models and observations of SNe Ia will help constrain progenitor scenarios and improve our understanding of the explosion physics of these events.
ADVISOR(s): Dr. Robert Fisher, Department of Physics (Robert.fisher@umassd.edu)
COMMITTEE MEMBERS: Dr. Sigal Gottlieb, Department of Mathematics Dr. Vijay Varma, Department of Mathematics
TXT 105
Dr. Robert Fisher
robert.fisher@umassd.edu