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Full-Text Articles in Physical Sciences and Mathematics
Osiris-Rex Surface Imaging To Constrain Properties Of The Asteroid (101955) Bennu, Alicia Allen
Osiris-Rex Surface Imaging To Constrain Properties Of The Asteroid (101955) Bennu, Alicia Allen
Honors Undergraduate Theses
This study used images taken from the OSIRIS-REx spacecraft sample-return mission and projected onto a three-dimensional shape model to determine surface properties of the asteroid (101955) Bennu. Two major projects were completed. For the first project, images of the pre-sampled Nightingale site and post-sampled Nightingale were compared to determine how the TAGSAM sampling maneuver effected the surface of the asteroid directly at the sampling site and in the surrounding area. This analysis demonstrated how spacecraft can potentially affect a small body during this and future sample-return missions. For the second project, several craters on Bennu’s surface were selected and all …
Atmospheric Retrieval: Bayesian Methods, Machine Learning, And Application To Exoplanets, Michael Himes
Atmospheric Retrieval: Bayesian Methods, Machine Learning, And Application To Exoplanets, Michael Himes
Electronic Theses and Dissertations, 2020-
Atmospheric retrieval is the inverse modeling method where atmospheric properties are constrained based on measured spectra. Due to the low signal-to-noise ratios of exoplanet observations, exoplanetary retrieval codes pair a radiative transfer (RT) simulator with a Bayesian statistical framework in order to characterize the distribution of atmospheric parameters that could explain the observations (the posterior distribution). This requires on the order of 106 RT model evaluations, which requires hours to days of compute time depending on model complexity. In this work, I investigate atmospheric retrieval methods and apply them to observations of hot Jupiters. Chapter 2 presents a set of …
Spectral Characterization And Age Of The Moon And Primitive Asteroids, Vanessa Lowry
Spectral Characterization And Age Of The Moon And Primitive Asteroids, Vanessa Lowry
Electronic Theses and Dissertations, 2020-
In this dissertation work we sought to answer questions about the age, composition, and origin of planetary bodies. We implemented multiple approaches to answer these questions. To determine the age of the Clarissa asteroid family we implemented a modified version of SWIFT: a Solar System integration software package by Levison & Duncan (1994) to account for gravitational as well as thermal perturbations. This work constrained the age of the Clarissa asteroid family to be 56 ± 6 My. Next, we used a sum to one constraint weighted least squares (STO WLS) modeling approach to model thermal infrared (TIR) spectra of …
Characterizing The Particle Size Distribution In Saturn's Rings Using Cassini Uvis Stellar Occultation Data, Stephanie Eckert
Characterizing The Particle Size Distribution In Saturn's Rings Using Cassini Uvis Stellar Occultation Data, Stephanie Eckert
Electronic Theses and Dissertations, 2020-
NASA's Cassini mission to Saturn revolutionized modern understanding of the planet's vast and intricate ring system. We use stellar occultation data from Cassini's UVIS High Speed Photometer (HSP) to characterize the particle size distribution in the rings with two methods. First, we discern the sizes of the smallest particles at ring edges by forward-modeling observed diffraction signatures which appear as spikes in the signal, the shape and amplitude of which depends on the size and abundance of the smallest particles. We then probe the upper end of the size distribution using occultation statistics. Although the distribution of photon counts in …
Characterizing The Effects Of Porosity And Particle Size On Tir Emissivity Spectral Features Of Olivine, Ryan Galinkin
Characterizing The Effects Of Porosity And Particle Size On Tir Emissivity Spectral Features Of Olivine, Ryan Galinkin
Electronic Theses and Dissertations, 2020-
We generated a series of 15 particulate San Carlos olivine samples with varying porosity and particle size. We created five different particle size distributions and each particle size distribution was prepared with three different packing techniques. These samples were then imaged under a microscope and a binarization thresholding technique was used to determine each sample's surface porosity by the ratio of dark, void pixels to the total number of pixels in each image. Our results show that we could estimate surface porosity from the analysis of a microscopic image, a non-destructive technique. These samples were then placed in the Planetary …