Planet Nine
A hypothesized ninth planet of 5-10 Earth masses, colloquially called "Planet Nine", has been suggested as an explanation for the observed clustering in the periastra of extreme trans-Neptunian objects (TNOs) in the distant solar system. While Planet Nine’s existence has the potential to alleviate tensions in observations of the outer solar system, the planet has yet to be found.
One of my research interests is the search for Planet Nine and its implications for the solar system. I have approached this question in two ways: (1) through a feasibility study examining gravitational probes of Planet Nine and (2) through a direct, reflected light search.
I proposed a novel method to search for Planet Nine by probing its gravitational influence on minor planets within the solar system using stellar occultation measurements. In addition to finding undiscovered masses in the distant solar system, occultations also offer the potential to directly rule out undiscovered bodies — something that is difficult to do in a direct, reflected light search. In my work, I demonstrated that precise positional measurements for a large (N>225) sample of Jovian Trojan asteroids would be sufficient to distinguish the signatures of Planet Nine from those of the Kuiper belt and to confirm Planet Nine’s existence (or non-existence). For a brief overview of this project, check out my first research highlight here.
I am also leading a shift-stacking survey of the outer solar system to look for Planet Nine and other distant TNOs using the Transiting Exoplanet Survey Satellite (TESS) dataset. To learn more about this project, read my fourth research highight here.