Physical Sciences and Mathematics Commons^™

Spectropolarimetry Of Epsilon Aurigae: Probing Stellar And Disk Atmospheres, Kathleen M. Geise

Electronic Theses and Dissertations

The bright eclipsing binary system epsilon Aurigae offers a unique opportunity to uncover physical mechanisms contributing to disk formation and evolution and to explore the relationship between photospheric anisotropies, stellar pulsation and mass loss. This research contributes to our understanding of stellar evolution in the context of binary stars. The research also offers the opportunity to investigate disk formation and evolution significant to our understanding of protoplanetary disks now seen in many star systems. Lastly, the project considers radiative transfer of polarized light that contributes to diverse fields such as atmospheric studies of exoplanets.

My objective is to understand the …

High-Precision Time-Series Photometry For The Discovery And Characterization Of Transiting Exoplanets., Karen Alicia Collins 1962-

Electronic Theses and Dissertations

The discovery of more than a thousand planets orbiting stars other than the Sun (i.e. exoplanets) over the past 20 years has shown that planetary systems are commonplace in the Milky Way galaxy. However, these discoveries are only a starting point in the quest to answer one of the most compelling questions posed by mankind for centuries – "are we alone in the universe?". This research aims to help build the foundation needed to search for that answer by optimizing data reduction techniques, determining and refining fundamental properties of known exoplanets, and searching for new exoplanets. Many exoplanets have been …

Identification Of High Energy Cosmic Ray Electrons Using Advanced Techniques In Calet And Fermi Lat, Aaron James Worley

Electronic Theses and Dissertations

Measurements of the cosmic ray electron spectrum have received much attention over the last decade as anomalies in both electron and positron observations have been detected independently by several experiments. The profound possible implications in the fields of high energy astrophysics and particle physics have allowed for many interpretations on the origin of these inconsistencies in the spectra. This research focuses on two space-borne cosmic radiation experiments at different stages in their mission lifetimes: the Calorimetric Electron Telescope (CALET) and the Fermi Large Area Telescope (LAT). We explore the proton-electron discriminating capabilities of the CALET instrument through Monte Carlo simulations. …

Observations, Thermochemical Calculations, And Modeling Of Exoplanetary Atmospheres, Jasmina Blecic

Electronic Theses and Dissertations

This dissertation as a whole aims to provide the means to better understand hot-Jupiter planets through observing, performing thermochemical calculations, and modeling their atmospheres. We used Spitzer multi-wavelength secondary-eclipse observations to characterize planetary atmospheres. We chose targets with high signal-to-noise ratios, as their deep eclipses allow us to detect signatures of spectral features and assess planetary atmospheric structure and composition with greater certainty. Chapter 1 gives a short introduction. Chapter 2 presents the Spitzer secondary-eclipse analysis and atmospheric characterization of WASP-14b. The decrease in flux when a planet passes behind its host star reveals the planet dayside thermal emission, which, …

Spectral Study Of Asteroids And Laboratory Simulation Of Asteroid Organics, Kelsey Hargrove

Electronic Theses and Dissertations

We investigate the spectra of asteroids at near- and mid-infrared wavelengths. In 2010 and 2011 we reported the detection of 3 ?m and 3.2-3.6 ?m signatures on (24) Themis and (65) Cybele indicative of water-ice and complex organics [1] [2] [3]. We further probed other primitive asteroids in the Cybele dynamical group and Themis family, finding diversity in the shape of their 3 ?m [4] [5] [6] and 10 ?m spectral features [4]. These differences indicated mineralogical and compositional variations within these asteroid populations. Also in the mid-infrared region we studied a larger population of asteroids belonging to the Bus …

Characterizing Exoplanet Atmospheres: From Light-Curve Observations To Radiative-Transfer Modeling, Patricio Cubillos Vallejos

Electronic Theses and Dissertations

Multi-wavelength transit and secondary-eclipse light-curve observations are some of the most powerful techniques to probe the thermo-chemical properties of exoplanets. Although the large planet-to-star brightness contrast and few available spectral bands produce data with low signal-to-noise ratios, a Bayesian approach can robustly reveal what constraints we can set, without over-interpreting the data. Here I performed an end-to-end analysis of transiting exoplanet data. I analyzed space-telescope data for three planets to characterize their atmospheres and refine their orbits, investigated correlated noise estimators, and contributed to the development of the respective data-analysis pipelines. Chapters 2 and 3 describe the Photometry for Orbits, …

Binary Star Systems With Asymmetrically Heated Disks: Thermal Phase Curves For The Disk In Epsilon Aurigae, Richard Luther Pearson Iii

Electronic Theses and Dissertations

Epsilon Aurigae is a long-period eclipsing binary that contains a warm F-star (~7750 K) and a circumstellar disk enshrouding a hidden companion, likely to be a hot B-star (>15,000 K). The eclipse itself lasts just over two years---thanks, in part, to the size of the disk---and occurs every 27.1-years. Its evolutionary status is still debated, along with the true nature of each stellar component, due to the high uncertainty in its parallax. The disk is similarly debated from the near absence of solid state infrared spectral features indicating its composition, particle size distribution, and density. An investigation of a …