Constraining Type Ia Supernova Progenitor Scenarios with Extremely Late-time Photometry of Supernova SN 2013aa
Physical and Biological Sciences
Physics (Astrophysics) Department Senior Thesis Requirement
Type Ia supernovae (SNe Ia) are cataclysmic stellar explosions whose light outshines entire galaxies. These incredible yet short-lived bursts of light are thought to be the result of a thermonuclear explosion involving a white dwarf star in a binary star system. SNe Ia have proven quite significant in the realm of cosmology due to their relatively consistent luminosities. Standardizing this luminosity has allowed us apply SNe Ia as distance metrics in the observable universe. Even more groundbreaking, SNe Ia are used in calculating the acceleration of the universe and utilized as probes for the elusive “dark energy.” Furthermore, SNe Ia explosions generate periodic elements that contribute significantly to the chemical composition of galaxies. However, despite all the applications of SNe Ia, our understanding of the exact binary star system (progenitor system) responsible for these remarkable events is incomplete. The two competing theories involve either a collision of two white dwarf stars or the explosion of a white dwarf star as it acretes mass from a larger binary companion. Without a more comprehensive picture of the explosion mechanism behind SNe Ia, their applications in various sects of astrophysics will continue to contain statistical uncertainties.
This work analyzes specific Type Ia supernova, SN 2013aa, and places constraints on its progenitor system. SN 2013aa was imaged with the Hubble Space Telescope in March of 2017 and we were able to detect the remnants of the supernova at an incredible 1500 days after explosion. Using this late-time luminosity, combined with data from early-time observations in 2013 and 2014, we were able to determine the masses of radioactive elements produced by SN 2013aa such as Cobalt-56, Cobalt-57, and Iron-55. From this, we calculated a ratio of radioactive isotope masses, which we then compared to that predicted by SNe Ia computer simulations. This allowed for us to hypothesize that SN 2013aa was caused by the violent merger of two white dwarf stars. Our study is only the fifth ever to be done using such late-time photometry of a Type Ia supernova. These results will add to the communities’ understanding on the origins of these impressive stellar explosions.
