Simulating the impact of stellar flares on the climate and habitability of terrestrial Earth–like exoplanets
Ridgway, R
Date: 5 June 2023
Thesis or dissertation
Publisher
University of Exeter
Degree Title
PhD in Physics
Abstract
Stellar flares present challenges to the potential habitability of terrestrial planets orbiting M dwarf stars through inducing changes in the atmospheric composition and irradiating the planet's surface in large amounts of ultraviolet light. To examine their impact, we have coupled a general circulation model called the Met Office ...
Stellar flares present challenges to the potential habitability of terrestrial planets orbiting M dwarf stars through inducing changes in the atmospheric composition and irradiating the planet's surface in large amounts of ultraviolet light. To examine their impact, we have coupled a general circulation model called the Met Office Unified Model with a chemical kinetics scheme to examine the response and changes of an Earth-like atmosphere to stellar flares and coronal mass ejections. I have implemented enhancements to the chemical kinetics framework to include the effects of photolysis, stellar energetic protons, and deposition. This was tested with a series of chemical networks with increasing complexity. I find that a M dwarf with stellar flares increases the amount of ozone in the atmosphere by a factor of 20 compared to a quiescent M dwarf. I find that coronal mass ejections abiotically generate significant levels of potential bio-signatures such as \ce{N2O}, and do not have a large impact on the amount of ozone. The changes in atmospheric composition cause a moderate decrease in the amount of ultraviolet light that reaches the planet's surface, suggesting that while flares are potentially harmful to life, the changes in the atmosphere due to a stellar flare act to reduce the impact of the next stellar flare.
Doctoral Theses
Doctoral College
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