Date:
Friday, April 13, 2012, 11:00am to 12:00pm
The Ph.D. colloquium by Sarah Ballard will be held on Friday, April 13, at 11 AM in Phillips Auditorium.
At 2 PM, Sarah will defend her thesis in the Classroom (A-101).
Talk Title: In Pursuit of New Worlds: Searches for and Studies of Transiting Exoplanets from Three Space-Based Observatories
Abstract: The first part of this thesis describes searches for additional transiting planets in known exoplanet systems, using time series photometry gathered as part of the NASA EPOXI Mission. Using the high-cadence, high-precision EPOXI light curves spanning weeks for each star, we searched six exoplanetary systems for signatures of additional transiting planets. These six systems include five hosts to hot Jupiters: HAT-P-4, TrES-3, TrES-2, WASP-3, and HAT-P-7, and one host to a hot Neptune: GJ 436. We detail a search for additional transits of a hypothesized planet smaller than the Earth, whose presence was suggested by the EPOXI observations of GJ 436. In that study, we demonstrate the sensitivity of Warm Spitzer observations to transits of a sub-Earth-sized planet. We describe the characterization and validation of the Kepler-19 system, which hosts one transiting 2.2 R_Earth planet around a 0.85 R_Sun star. We demonstrate the authentic planetary nature of the transit si!
gnal with an analysis that combines information from high-resolution spectroscopy, the shape of the transit light curve, adaptive optics imaging, and near-infrared transits of the planet gathered with Warm Spitzer. The sinusoidal variation in the transit times of Kepler-19b, with amplitude of 5 minutes and period of 300 days, indicate the presence of an additional perturbing body, and comprise the first definitive detection of a planet using the transit timing variation method. Finally, we present evidence for the validation of a 2.0 R_Earth planet residing in the habitable zone of a low-mass star, Kepler Object of Interest 1361.01. We discuss the theoretical composition of the planet, and address issues specific to habitability of planets orbiting M dwarfs.
At 2 PM, Sarah will defend her thesis in the Classroom (A-101).
Talk Title: In Pursuit of New Worlds: Searches for and Studies of Transiting Exoplanets from Three Space-Based Observatories
Abstract: The first part of this thesis describes searches for additional transiting planets in known exoplanet systems, using time series photometry gathered as part of the NASA EPOXI Mission. Using the high-cadence, high-precision EPOXI light curves spanning weeks for each star, we searched six exoplanetary systems for signatures of additional transiting planets. These six systems include five hosts to hot Jupiters: HAT-P-4, TrES-3, TrES-2, WASP-3, and HAT-P-7, and one host to a hot Neptune: GJ 436. We detail a search for additional transits of a hypothesized planet smaller than the Earth, whose presence was suggested by the EPOXI observations of GJ 436. In that study, we demonstrate the sensitivity of Warm Spitzer observations to transits of a sub-Earth-sized planet. We describe the characterization and validation of the Kepler-19 system, which hosts one transiting 2.2 R_Earth planet around a 0.85 R_Sun star. We demonstrate the authentic planetary nature of the transit si!
gnal with an analysis that combines information from high-resolution spectroscopy, the shape of the transit light curve, adaptive optics imaging, and near-infrared transits of the planet gathered with Warm Spitzer. The sinusoidal variation in the transit times of Kepler-19b, with amplitude of 5 minutes and period of 300 days, indicate the presence of an additional perturbing body, and comprise the first definitive detection of a planet using the transit timing variation method. Finally, we present evidence for the validation of a 2.0 R_Earth planet residing in the habitable zone of a low-mass star, Kepler Object of Interest 1361.01. We discuss the theoretical composition of the planet, and address issues specific to habitability of planets orbiting M dwarfs.