A study of white dwarfs: cataclysmic variables and double-detonation supernovae

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
University of Alabama Libraries

Novae, be it classical, dwarf, or supernovae, are some of the most powerful and luminous events observed in the Universe. Although they share the same root, they are produced by different physical processes. We research systems capable of experiencing novae with the intention of furthering our understanding of these astrophysical phenomena. A cataclysmic variable is a binary star system that contains a white dwarf with the potential of undergoing classical or dwarf novae. A recent observation of a white dwarf within one of these systems was found to have an unusually high surface temperature for its orbital period. The discovery contradicts current evolutionary models, motivating research to determine a theoretical justification for this outlier. Using MESA (Modules for Experiments in Stellar Astrophysics), we simulated novae for a progenitor designed to represent a white dwarf in an interacting binary. We developed post-novae cooling timescales to constrain the temperature value. We found the rate at which classical novae cool post-outburst (< 1 K yr−1) is in general agreement with the four−year follow-up observation (∼ 2 K). The evolution of white dwarfs during double- detonation type Ia supernovae was also studied. The progenitors capable of producing these events are not fully established, requiring a consistent model to be developed for parametric analysis. Three improvements were made to the simulation model used in (Townsley et al., 2019): the inclusion of a de-refinement condition, a new particle distribution, and a burning limiter. The focus here was to enhance the computational efficiency, offer better representation of particles in the supernova ejecta, and control the nuclear energy release. These developments were employed to test double-detonation scenarios capable of producing spectra analogous to type Ia supernovae, which will offer insight into their prevalence and strengthen their use in measuring cosmological distance.

Electronic Thesis or Dissertation