Date on Master's Thesis/Doctoral Dissertation
Physics and Astronomy
Committee Co-Chair (if applicable)
Astronomical photometry; Extrasolar planets--Detection
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 discovered using the radial velocity (RV) technique to measure small variations in a star’s motion that are gravitational induced by an orbiting planet. The RV signal reveals the planetary mass, orbital period, and orbital eccentricity. If an exoplanet crosses the face of its host star (i.e. transits) from the perspective of the observer, it causes an apparent periodic dimming of the star. The depth and shape of those brightness variations reveal the planet’s radius, its transit time, and some orbital characteristics. Combining the mass and radius measurements, a planet’s mean density can be calculated, thus constraining its composition. During transit, part of the star’s light passes through the planetary atmosphere on its way to Earth, facilitating atmospheric measurements. Monitoring a planet’s transit timing variations (TTVs) on many epochs may reveal the presence of another planet in the system due to gravitational interactions. I report the development of a new tool, AstroImageJ (AIJ), that provides an interactive environment for the optimal extraction and analysis of high-precision photometry from time-series observations. Based on AIJ photometry, I report high-precision measurements of system parameters and tight upper limits on TTVs derived from global analyses of 23 WASP-12b and 18 Qatar-1b complete transits. I also report the detection of sodium in the atmosphere of the exoplanet HD 189733b, the detection of z′ band emission from the recently discovered hot brown dwarf, KELT-1b, and the discovery and characterization of the transiting hot-Saturn exoplanet, KELT-6b. Data for this research have been collected using the research-grade 0.6 m Moore Observatory RC (MORC) telescope, which is located near Louisville, Kentucky, and operated by the University of Louisville.
Collins, Karen Alicia 1962-, "High-precision time-series photometry for the discovery and characterization of transiting exoplanets." (2015). Electronic Theses and Dissertations. Paper 2104.