Page limit information on the Guidlines/Checklist page is somehwat conflicting. The total page limit of the attached pdf is stated to be 8 pages. However it also states that "References should be listed at the end of the proposal and do not count against the page limits." The total attached pdf is 9.1 pages, but 1.1 pages is just references. Actual proposal text+figures is within 8 pages. -185628976 Assigned ID: 704 ----- Attempting Submission 1 (Fri Mar 06 19:35:08 GMT 2020) ----- HST Phase I Proposal 704 successfully submitted. Receipt: # 704-1 ----- Attempting Submission 2 (Fri Mar 06 21:52:44 GMT 2020) ----- Transit spectroscopy with HST (and upcoming JWST) pioneered our understanding of extra-solar planet atmospheres spanning ultra-Hot Jovian worlds to temperate super-earths. This vast planetary diversity leads to many key questions about the nature of planetary climate, composition, and chemistry. Questions regarding the processes influencing molecular abundances, intrinsic elemental composition, and heat transport as well as many others can only be addressed via the interplay between spectral data and atmospheric models. We propose to develop a new large, publicly available, 1D self-consistent radiative-convective equilibrium spectral model grid to advance our understanding of broad planetary atmosphere population trends and to perform Bayesian atmospheric parameter estimation. This new grid will be applied to published and archival HST spectrophotometric transit observations composed of more than 1000 HST orbits over wavelengths covered by STIS, WFC3, and soon UVIS, (as well as countless hours with Spitzer) obtained over the past two decades. Results from this investigation will be used to make predictions for both upcoming HST and JWST spectra for specific planets and also population level predictions in uncharted parts of the planetary phase space where new observations will provide maximal hypothesis discriminating power. We have collated a cohesive team with experts in modeling and observations/data analysis with years of experience in transit spectroscopy observations and modeling. PI Line is an expert on atmospheric chemistry and spectral modeling/retrieval. Line has also developed the new 1D-RC code, the beginning of the model grid, and have already applied it in several applications described in the proposal document. Aishwarya Iyer is a graduate student with Line, learning the art of ultra-hot exoplanet atmosphere and M-dwarf photosphere radiative-convecitve modeling and retrievals. Co-I's Megan Mansfield, Kevin Stevenson, Jacob Bean, and Brian Kilpatrick all have experience in leading small and large HST GO and Treasury programs. They are experts in planning and executing HST WFC3 observations as well as their subsequent data analysis. They will assist in the re-reduction and analysis of unpublished/archival HST data (as demonstrated in Figure 4 of the proposal document). Vivien Parmentier, Eliza Kempton, and Jonathan Fortney are experts in three dimensional circulation modeling and 1D modeling of exoplanet atmospheres. Ehsan Gharib-Nezhad is an expert in exoplanet relevant opacities and has experience generating useable opacities from the ExoMol database. Exoplanets and Exoplanet Formation Stellar Physics and Stellar Types 0 Regular false false false true false SUPPORTED