DIX Planetary Science Seminar

Survey missions have identified over 6000 extrasolar planets. These planets exhibit a broad diversity of sizes, orbital properties, and system architectures, all tracers of planet formation and evolution. Although the basic paradigm of planet formation by oligarchic growth is generally uncontroversial, many of the details remain poorly understood. In most cases our knowledge is limited primarily by the quality and sample size of available measurements. In this talk, I will present recent measurements of orbital eccentricities for 1600 planets, demonstrating that large planets (4 –16 Earth-radii) are four times more eccentric than small planets (0.5 – 4 Earth-radii), pointing to distinct formation channels for these two size groups. I will also present evidence that giant impacts and mergers play an important role in the formation of small planets, and that super-Jovian planets likely form by a combination of both bottom-up mechanisms (i.e. core accretion) and top-down mechanisms (i.e. gravitational instability). I will conclude by discussing how "big data" analysis methods will allow our community to make the most of new observations (e.g. from Gaia, Keck Planet Finder, and the Roman Space Telescope) which are expected to dramatically expand the quantity and diversity of the Galactic exoplanet census.