Inferring "True" Small Planet Demographics with the Magellan-TESS Survey

Dr. Johanna Teske (Carnegie Earth & Planets Laboratory)
Tuesday, December 8, 2020 - 11:00am

The last decades of exoplanet exploration have revealed that the diversity of planets within the Galaxy far exceeds that within our solar system. Specifically, Kepler revealed a new population of 1-3 Rearth short period planets that seem to bridge the gap between the giants and terrestrials in our own bimodal planetary system. Recent results on the characterization of these planets have presented two questions: (1) Is there a range of super-Earth and/or sub-Neptune formation mechanisms? and (2) What is the precise and accurate planet mass-radius relation in the <3 Rearth regime? The Magellan-TESS Survey (MTS) is designed to address these two questions in a statistically robust, open framework that can connect observed planet distributions to true underlying populations. It will include mass constraints, host star compositions, and system architectures of 30 small planets detected by TESS across a range of insolation fluxes. Its statistical robustness arises from quantifiable and uniformly applied choices for target selection and observation cadencing, a new feature compared to most previous transiting planet follow-up surveys. In this talk I will (1) present the latest results from the MTS, including our hierarchical Bayesian modeling of the mass-radius relation, and (2) discuss next steps for the survey and plans for complementary atmospheric follow-up. Overall, the MTS-style approach to population studies will become increasingly important as we move deeper into the era of exoplanet characterization where observational constraints are more technically challenging and expensive.

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