Unraveling Warm, Large Exoplanet (WaLE) Origins From TESS Observations

Warm, Large Exoplanets (WaLEs) — defined here as planets larger than 6 Earth radii with orbital periods 8-200 days — are a key missing piece in our understanding of how planetary systems form and evolve. It is currently debated whether WaLEs form in situ, undergo disk or high eccentricity tidal migration, or even have a mixture of origin channels (see attached Figure for illustration). These different classes of origin channels lead to different expectations for WaLEs' properties, such as their eccentricity distribution and occurrence rate. So far only a few dozens WaLEs are known and the characterization of their eccentricity distribution and occurrence rates is limited by the small sample size. We take advantage of the TESS survey and perform a uniform search of WaLE candidates in the TESS Full Frame Images (FFIs) around stars brighter than 12th Tmag in the first year of TESS data. I will present our discovery of ~80 TESS WaLE candidates and the characterization of their properties (e.g., eccentricities, transit-timing variations) from their lightcurves. I will further show new results on the underlying eccentricity distribution and occurrence rate of these WaLE candidates using hierarchical Bayesian modeling. Lastly, I will discuss the implications of our findings for WaLEs' origin channels, specifically on which one or more origin channels predominantly contributed to the WaLE population.