UC Irvine

The field of exoplanet science is fast approaching the capability to detect life on distant planets. The successful launch of the James Webb Space Telescope (JWST) will allow us to probe into the atmospheres of some, and the future Habitable Worlds Observatory (HWO) and thirty-meter class telescopes will allow us to directly image our closest exoplanetary neighbors. To accomplish their science goals, however, these facilities require a well-curated list of targets that are well understood. Today, most planets are not understood deeply, and the very nearest exoplanet systems—exclusively accessible via the radial velocity (RV) method—remain challenging to characterize, in no small part due contamination originating from stellar astrophysics of their host stars. The best analysis techniques for disentangling stellar noise from genuine exoplanetary signals is key to the future of exoplanet science. In this work, I focus on quantitatively comparing different ways to combine photometric data with RVs, first to deeply understand systems with minimal stellar contamination, and finally to probe into those most challenging systems. Such analyses are essential steps to finding Earth twins, a crucial prerequisite in the quest to learn if indeed we are alone in the universe. First I characterize three transiting planets, discovered by the Transiting Exoplanet Survey Satellite (TESS), and a combine RVs and ground-based photometry to improve our understanding of their nature. I then turn my focus to exoplanet systems for which stellar variability presents a major challenge to measuring the detailed properties of the planets. My analysis of the young multiplanet system TOI-1136 combines transit times and RVs to touch upon many of the most important aspects of current exoplanet science, including atmospheres, formation, and evolution. I finally study the relationship between RVs and photometry, and I investigate the best ways to transfer knowledge of stellar variability from photometric to RV datasets in order to more reliably detect exoplanets and measure their masses.