# # Program information file # PROGRAM_ID 2022B068 PROGRAM_TITLE Probing the Formation of Directly Imaged Exoplanets via Robust Atmospheric Characterization PROGRAM_INV1 Zhoujian Zhang PROGRAM_INV2 Brendan Bowler PROGRAM_INV3 Keith Hawkins PROGRAM_INV4 Paul Molliere PROGRAM_INV5 Caroline Morley PROGRAM_SCICAT extra-solar planets PROGRAM_ABSTRACT_BEG Directly imaged exoplanets are appealing targets for studying self-luminous planet atmospheres, yet their formation remains unclear. One promising approach to investigate imaged planets' formation is to compare the [Fe/H] and carbon-to-oxygen ratios [C/O] between the planets and their host stars since different mechanisms predict distinct relative abundance patterns. Robustly characterizing abundances of exoplanets is difficult, given the systematics of model atmospheres, but can be achieved by first focusing on the growing census of brown dwarfs that are wide-orbit companions to stars. These companions are excellent analogs of imaged planets and share [Fe/H] and C/O as their hosts, making them crucial benchmarks for quantifying the systematics of exoplanet model atmospheres. We are conducting the first uniform spectroscopic characterization of [Fe/H] and C/O for imaged planets, brown dwarf benchmarks, and their host stars, to investigate the formation of giant planets. Here we propose to obtain IRTF/SpeX spectroscopy for 12 imaged planets and brown dwarfs [prism], and 9 M-type host stars [SXD]. We will then analyze our proposed observations and the existing data to generate the first uniform catalog of these objects' [Fe/H] and C/O properties. Our program aims to compare imaged planets' and their hosts' elemental abundances as a function of orbital separations for the first time, to reliably probe the giant planet formation at different sites of planetary systems. PROGRAM_ABSTRACT_END