Physics Master of Science Thesis Defense by Chackochan Joji
Abstract:
Type Ia supernovae (SNe Ia) are among the most common types of luminous astrophysical transients. They are thought to arise from the thermonuclear explosion of mass-accreting white dwarfs (WDs) in binary systems. Due to their consistent peak luminosities, SNe Ia are used as standardizable candles to measure the expansion rate of the universe. A subluminous subclass of these events, known as Type Iax supernovae, is believed to be the result of a failed or partial detonation of WDs. Pa 30 has recently been identified as the remnant of the historical supernova SN 1181, which reveals an unusual filamentary morphology with a WD at its center. Recent studies indicate that SN 1181 was likely a sub-luminous event, classified as a Type Iax supernova, possibly originating from a merger between carbon-oxygen (C/O) and oxygen-neon (O/Ne) WDs.
In this thesis, we investigate failed detonations of Type Iax supernovae within the context of the double-degenerate merger channel. Specifically, we consider a binary system consisting of a C/O WD and an O/Ne WD. In this scenario, the secondary C/O WD is tidally disrupted and merges with the O/Ne WD, forming an accretion disk around the primary. Due to instabilities within the disk, a carbon detonation is triggered on the surface of the primary, while leaving it largely intact. The total nuclear energy released in this event is lower than that of a normal SNe Ia, consistent with the properties of the SNe Iax. We further explore the detonation mechanism, the characteristics of the resulting remnant, and the broader implications of this model for understanding the physics of Type Iax supernovae.
Advisor:
Dr. Robert Fisher, Department of Physics (Robert.fisher@umassd.edu)
Committee members:
Dr. David Kagan, Department of Physics
Dr. Renuka Rajapkse, Department of Physics
SENG 201