Seminar: Sarah Ballard [MIT]
The Grand Planetary Ensemble
Dec 1, 2016 11:00 AM to Dec 1, 2016 12:00 PM at Building 8 - Room 241The Solar System furnishes the most familiar planetary architecture: many planets, orbiting nearly coplanar to one another. However, the most common planetary systems in the Milky Way orbit much smaller M dwarf stars, and these may present a very different blueprint. The Kepler data set has uncovered more than 100 exoplanets orbiting stars half the mass of the sun and smaller. Half of these planets reside in systems with at least one additional planet. The data much prefer a model with two distinct modes of planet formation around M dwarfs, which occur in roughly equal measure. One mode is one very similar to the Solar System in terms of multiplicity and coplanarity, and the other is very dissimilar. In the context of the “Kepler Dichotomy,” we've studied the broadband transmission spectra (with data from Kepler and hundreds of hours of Spitzer observations) of dozens of M dwarf planets: half of which reside in one type of planetary system, and half in the other. Although the data set is too small and the observational uncertainty too large to characterize any one system alone, I'll describe ensemble trends between planetary dynamics and atmospheric content and how we're leveraging these studies to maximize the return of forthcoming JWST studies of potentially habitable exoplanets.