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In this study, the influence of fluid mixing on temperature and geochemistry of hot spring fluids is investigated. Yellowstone National Park (YNP) is home to a diverse range of hot springs with varying temperature and chemistry. The mixing zone of interest in this paper, located in Geyser Creek, YNP, has

In this study, the influence of fluid mixing on temperature and geochemistry of hot spring fluids is investigated. Yellowstone National Park (YNP) is home to a diverse range of hot springs with varying temperature and chemistry. The mixing zone of interest in this paper, located in Geyser Creek, YNP, has been a point of interest since at least the 1960’s (Raymahashay, 1968). Two springs, one basic (~pH 7) and one acidic (~pH 3) mix together down an outflow channel. There are visual bands of different photosynthetic pigments which suggests the creation of temperature and chemical gradients due to the fluids mixing. In this study, to determine if fluid mixing is driving these changes of temperature and chemistry in the system, a model that factors in evaporation and cooling was developed and compared to measured temperature and chemical data collected downstream. Comparison of the modeled temperature and chemistry to the measured values at the downstream mixture shows that many of the ions, such as Cl⁻, F⁻, and Li⁺, behave conservatively with respect to mixing. This indicates that the influence of mixing accounts for a large proportion of variation in the chemical composition of the system. However, there are some chemical constituents like CH₄, H₂, and NO₃⁻, that were not conserved, and the concentrations were either depleted or increased in the downstream mixture. Some of these constituents are known to be used by microorganisms. The development of this mixing model can be used as a tool for predicting biological activity as well as building the framework for future geochemical and computational models that can be used to understand the energy availability and the microbial communities that are present.

ContributorsOrrill, Brianna Isabel (Author) / Shock, Everett (Thesis director) / Howells, Alta (Committee member) / School of Life Sciences (Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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The James Webb Space Telescope (JWST) is expected to revolutionize the current understanding of Jovian worlds over the coming decade. However, as the field pushes towards characterizing cooler, smaller, “terrestrial-like” planets, dedicated next-generation facilities will be required to tease out the small spectral signatures indicative of biological activity. Here, the

The James Webb Space Telescope (JWST) is expected to revolutionize the current understanding of Jovian worlds over the coming decade. However, as the field pushes towards characterizing cooler, smaller, “terrestrial-like” planets, dedicated next-generation facilities will be required to tease out the small spectral signatures indicative of biological activity. Here, the feasibility of determining atmospheric properties, from near to mid-infrared transmission spectra, of transiting temperate terrestrial M-dwarf companions, has been evaluated. Specifically, atmospheric retrievals were utilized to explore the trade space between spectral resolution, wavelength coverage, and signal-to-noise on the ability to both detect molecular species and constrain their abundances. Increasing spectral resolution beyond R=100 for near-infrared wavelengths, shorter than 5um, proves to reduce the degeneracy between spectral features of different molecules and thus greatly benefits the abundance constraints. However, this benefit is greatly diminished beyond 5um as any overlap between broad features in the mid-infrared does not deconvolve with higher resolutions. Additionally, the inclusion of features beyond 11um did not meaningfully improve the detection significance nor abundance constraints results. The findings of this study indicate that an instrument with continuous wavelength coverage from approximately 2-11um and with a resolution of R~50-300, would be capable of detecting H2O, CO2, CH4, O3, and N2O in the atmosphere of an Earth-analog transiting an M-dwarf (magK=8.0) within 50 transits, and obtain better than an order-of-magnitude constraint on each of their abundances.

The Origins Space Telescope (Origins) is one of four flagship mission concepts, under review by the 2020 Decadal Survey, that may take the mantle of the next-generation space-based observatory. In conjunction with this research, a secondary trade space study was performed on behalf of the Origins Exoplanets Working Group. The primary purpose of this collaboration was to provide a scientific basis to the technical specifications for the mid-infrared detectors onboard the Mid-Infrared Spectrometer Camera Transit Spectrometer (MISC-T) instrument. The results of this work directly contributed to the alteration of the official technical specifications of the instrument design concept.
ContributorsTremblay, Luke (Author) / Line, Michael R (Thesis advisor) / Schkolnik, Evgenya (Committee member) / Walker, Sarah (Committee member) / Arizona State University (Publisher)
Created2019