Description
- Abstract:
- Thermal infrared spectroscopic measurements record not only compositional information about the properties of a target but also information about the environmental conditions in which the measurement was acquired. Spectral variations resulting from the cold and vacuum environment of airless planetary surfaces are much more significant than for surfaces modulated by atmospheres; this can greatly influence interpretations of physical and chemical properties of those surfaces when using emissivity spectra. S-type asteroids are one such category of airless planetary surfaces that is of great interest to the asteroid and planetary defense communities as they represent the most abundant objects in the inner main belt and near-Earth object populations. Because the S-types have been linked with ordinary chondrite meteorites, one can measure the latter under controlled asteroid-like conditions to probe how thermal and emissivity properties respond due to a cold and vacuum environment. This dissertation addresses knowledge gaps in the thermal emission properties of the ordinary chondrites and relevant planetary materials to advance our ability to interpret compositional and thermophysical properties of these meteorites and their parent bodies. In Chapter One, a detailed radiometric calibration of the Asteroid and Lunar Environment Chamber (ALEC) is presented and includes a new method for deriving emissivity spectra from thermal emission measurements of a sample and calibration targets that does not require common optical property assumptions present in other methods. In Chapter Two, a suite of mineral samples relevant to the ordinary chondrites is investigated at ambient and simulated asteroid conditions, and in Chapter Three modal mixtures of these minerals mimicking the ordinary chondrite mineral abundances are measured at the same conditions to probe how these materials are altered by the changing environmental conditions. In Chapter Four, thermally metamorphosed ordinary chondrite samples are characterized at the same experimental conditions as the minerals and mixtures, and their spectral alterations due to cold and vacuum conditions are investigated. In Chapter Five, representative emissivity data from the previous chapters are used to investigate how the spectral variation due to changing environmental conditions and data reduction methods will affect parameters relevant to asteroid thermophysical modeling.
- Notes:
- Thesis (Ph. D.)--Brown University, 2020
Access Conditions
- Rights
- In Copyright
- Restrictions on Use
- All rights reserved. Collection is open to the Brown community for research.
Citation
Bramble, Michael Stephen,
"Advancing Thermal Emission Spectroscopy of Ordinary Chondrites and their Parent Bodies with Laboratory Experiments in a Simulated Asteroid Environment"
(2020).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:1129442/
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Earth, Environmental and Planetary Sciences Theses and Dissertations
Theses and Dissertations for the Earth, Environmental and Planetary Sciences department....