Faculty Mentor
Dr. William R. Hix
Department (e.g. History, Chemistry, Finance, etc.)
Department of Physics and Astronomy
College (e.g. College of Engineering, College of Arts & Sciences, Haslam College of Business, etc.)
College of Arts & Sciences
Year
2018
Abstract
The nucleosynthesis which occurs in core-collapse supernovae (CCSN) is one of the most important sources of elements in the universe. Elements from Oxygen through Iron come predominantly from supernovae, and contributions of heavier elements are also possible through the r-process, the gamma process, and the light element primary process. The ejecta composition depends on the mechanism of the explosion, thus simulations of high physical fidelity are needed to explore which elements and isotopes CCSN can contribute to GCE. We will analyze the nucleosynthesis results from self-consistent CCSN simulations performed with CHIMERA, a multi-dimensional neutrino radiation-hydrodynamics code. We will present nucleosynthesis predictions for the explosion of a 9.6 solar-mass first-generation star, relying both on results of the 160 species nuclear reaction network used in CHIMERA and on post-processing with a more extensive network. The lowest mass iron core-collapse supernovae, like this 9.6 solar mass model, are distinct from their more massive brethren, with their explosion mechanism and nucleosynthesis resembling electron-capture supernovae resulting from Oxygen-Neon white dwarves. We highlight the differences between the nucleosynthesis of these models, discuss the need and mechanism to extrapolate the post-processing to times after the end of the simulation, and analyze the uncertainties this introduces.
Nucleosynthesis in Core-Collapse Supernovae
The nucleosynthesis which occurs in core-collapse supernovae (CCSN) is one of the most important sources of elements in the universe. Elements from Oxygen through Iron come predominantly from supernovae, and contributions of heavier elements are also possible through the r-process, the gamma process, and the light element primary process. The ejecta composition depends on the mechanism of the explosion, thus simulations of high physical fidelity are needed to explore which elements and isotopes CCSN can contribute to GCE. We will analyze the nucleosynthesis results from self-consistent CCSN simulations performed with CHIMERA, a multi-dimensional neutrino radiation-hydrodynamics code. We will present nucleosynthesis predictions for the explosion of a 9.6 solar-mass first-generation star, relying both on results of the 160 species nuclear reaction network used in CHIMERA and on post-processing with a more extensive network. The lowest mass iron core-collapse supernovae, like this 9.6 solar mass model, are distinct from their more massive brethren, with their explosion mechanism and nucleosynthesis resembling electron-capture supernovae resulting from Oxygen-Neon white dwarves. We highlight the differences between the nucleosynthesis of these models, discuss the need and mechanism to extrapolate the post-processing to times after the end of the simulation, and analyze the uncertainties this introduces.