Title: Constraining Planet Formation with Directly Imaged Exoplanets
In the past decade, several new jovian exoplanets at wide separations have been revealed using ground based telescopes equipped with adaptive optics systems. These planets, with masses between ~2-14 MJup, remain a puzzle for both major planet formation models – core accretion and gravitational instability. At the same time, they offer a powerful tool in the hunt for observational constraints of formation, as they can be characterized with both imaging and spectroscopy. I will describe our recent efforts to push beyond the discovery phase into the realm of detailed characterization of these planetary systems. Using the Keck adaptive optics instrument suite, we have been targeting known directly imaged planetary systems for orbital characterization and detailed mapping of their atmospheres. I will describe our findings, including the atmospheric abundance measurements for these planets, which can be used as a diagnostic of formation. Secondly, I will describe the results of a campaign with the Gemini Planet Imager (GPI) on Gemini South to discover new systems with direct imaging. We have surveyed over 500 stars with GPI and as a result, we have determined the where the peak of the giant planet distribution likely resides as a function of host star separation. We have also found that higher mass stars are much more likely to host Jovian planets than stars like the Sun. Finally, I will describe upcoming instrumentation efforts that will improve our ability to detect planets via direct imaging, including upgrades to the Gemini Planet Imager and new instruments in the planning phases for Keck and the future Thirty Meter Telescope.