Presentation #317.03D in the session “Exoplanet Populations: Observations and Demographics”.
A major bottleneck for transiting exoplanet demographics has been the lack of precise properties for most of the observed stars, as the transit method measures exoplanet radii relative to their host’s radii. We live in a golden era of host star characterization because of access to Gaia Data Release 2 (DR2) photometry, parallaxes, and proper motions, large-scale spectroscopic surveys, and ground-based photometric and spectroscopic follow-up. In this talk, I will present a sharpened view of Kepler exoplanet demographics using Gaia DR2 parallaxes. First, I will present a comprehensive classification of main sequence, subgiant, and giant stars in Kepler target sample. Using revised planet radii and incident fluxes, I will identify the planet radius gap, planets within the hot sub-Neptunian desert, the hot Jupiter inflation trend, and present an updated census of habitable zone planets. I will also present the Gaia-Kepler Stellar Properties Catalog, the first homogeneous Kepler catalog to include stellar ages, in addition to precise radii, masses, and mean stellar densities for Kepler target stars. I will reveal the first observational evidence of a stellar age dependence of the planet radius gap, where sub-Neptunes become super-Earths on roughly Gyr timescales. In addition, I will show that the planet radius valley exhibits a stellar mass dependence and provide stringent constraints that will be required to discern between the theories of core-powered mass-loss and photoevaporation. Finally, I will reveal that most planets within the hot sub-Neptunian desert only entered recently because of their host’s evolution, identify Jupiters with large radii at low incident fluxes, and demonstrate that planets in single and multiple transiting systems share the same age distribution.