Astrophysics Luncheon Seminar Advancing Spectral Retrievals in the Era of Large Space-based Telescopes Presented by Kat Feng University of California, Santa Cruz Monday, March 11, 2019 12:00 noon in 169-336 and on Webex Abstract Observations and models have revealed the complex and dynamic states of exoplanetary atmospheres. To understand their thermal structures and chemical abundances, the field has been moving towards inverse models, or "retrievals." The traditional retrieval assumes a 1D hemispherically averaged model to interpret data from complex 3D atmospheres. I show the importance of challenging this 1D assumption for an accurate understanding of a transiting hot Jupiter's thermal structure and chemical abundances. In particular, I demonstrate the biases of 1D retrievals on measured and simulated spectroscopic phase curve data. The coming decade also holds enormous potential for the direct imaging of exoplanets, fueled by NASA's upcoming Wide-Field InfraRed Survey Telescope (WFIRST) mission, the Habitable Exoplanet Imaging (HabEx) and the Large UltraViolet-Optical-InfraRed (LUVOIR) mission concepts. As such, I will present the first systematic exploration of retrievals on reflected-light data for the atmospheres of terrestrial exoplanets. Such a retrieval framework examines the feasibility of detecting key molecules like water vapor as a function of signal-to-noise ratio and resolution. This work demonstrates the necessity of retrievals in aiding instrument design. JPL Contact: Tiffany Kataria (3-4935)   Site Manager: Webmaster: CL 08-3220