Relevant Degree Programs
Graduate Student Supervision
Doctoral Student Supervision (Jan 2008 - May 2019)
The discovery of exoplanets on short orbital periods (P 10 Earth-masses. We compare the dynamical outcomes of gas-free and gas-embedded planetary systems, in which consolidation of a critical core was only possible in the gas-free simulations. In contrast, STIPs are resistant to instability when gas is present, resulting in coplanar and nearly circular systems. The instability of the configurations after 10 Myr increases if the eccentricity is perturbed to e~0.01. In some cases, the planet-disk interaction produces co-orbiting planets that are stable even when the gas is removed. We explore the transit detectability of these configurations and find that the coorbital transit signature is difficult to identify in current transit detection pipelines due to the system dynamics. To explore STIP evolution in the presence of an outer giant planet, we vary the semi-major axis of the perturber between 1 and 5.2 au. We find that the presence of the outer perturber, in most locations, only alters the STIP precession frequencies but not its evolution or stability. In those locations where the perturber causes secular eccentricity resonances, the STIP becomes unstable. Secular inclination resonances can affect the observed multiplicity of transiting planets by driving the orbits of one or more planets to inclinations about 16 degrees.
Debris discs are systems of dynamically evolved byproducts of the planet formation process. They can be used to test various planet formation theories. In my thesis I use submm-cm observations to characterize the debris in HD 141569 and Fomalhaut, as well as to investigate how stellar emission can serve as a confounding parameter in disc studies. HD 141569 is a unique system hosting a large B9.5 star, a complex circumstellar disc of gas and dust, and two M dwarf companions. Using ALMA data, I inferred the total gas mass of the system and directly imaged the inner and outer edge of the gas disc. Using ALMA and VLA data, I placed constraints on the morphology, mass, and dynamical state of the inner and outer dust discs. I used the properties of the gas and dust to argue that the system may be more accurately characterized as a young debris disc as opposed to a transitional disc. Fomalhaut is a commonly studied nearby debris system. I used ALMA observations to place tight constraints on the morphology, mass, and grain size distribution of the outer debris ring. In addition, I used ALMA and IR data to cast doubt on the existence of an asteroid belt in the inner system. To separate the emission from discs and their host stars, high angular resolution observations are necessary. When the resolution is still not sufficient to spatially separate the two, an accurate model of the stellar emission is required. I am the PI on an observational campaign entitled Measuring the Emission from Stellar Atmospheres at Submillimeter/millimeter wavelengths (MESAS). This project seeks to observe stars with no known debris at wavelengths commonly used for studying discs, build a spectral profile of the sub-millimetre to centimetre emission, and use these profiles as templates for the stellar emission in unresolved debris features.