1. On the detection of polycyclic aromatic hydrocarbons within dynamic surface features on Mars
- Author
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Campbell, Jacqueline D.
- Subjects
523.43 - Abstract
The aim of this thesis is to identify suitable environments for the detection of organic signatures on the Martian surface, to produce diagnostic spectra for organics in various Mars analogues, to establish the detectability limit of those organics using laboratory experiments and then compare laboratory results to measurements from Mars. The organics searched for in this work are Polycyclic Aromatic Hydrocarbons (PAHs), which are considered to be 'building blocks' for life, and can be a biomarker for extant life; they are abundant on Earth and throughout the universe, but so far are conspicuously absent on Mars, likely due to the high levels of ultraviolet radiation present on the Martian Surface. Therefore, dynamic processes on Mars that uncover previously shielded material on the Martian surface are identified, and various sites examined, to look at their suitability as potential candidates for PAH detection. The Martian South Polar Residual Cap (SPRC) has been chosen as a primary study site due to the abundance of CO2 ice sublimation features known as Swiss Cheese Terrain (SCT). These quasi-circular pits exhibit seasonal and long term retreat, exposing dust that had previously been trapped within the ice. The morphology and compositional changes of SCT over time are examined, and laboratory experiments in environmental cells have been carried out to establish base-line spectra for PAHs in SPRC and Mars regolith analogues, as well as the minimum amount of PAH necessary for detection from orbit by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). In addition, Recurring Slope Lineae (RSL) sites and analogues have been examined to provide baseline spectra and detectability limits for PAHs in non-polar dynamic features. This work intends to shed light on the question of these 'missing' organic molecules on Mars, and assist in the search for life on the Red Planet.
- Published
- 2021