# # Program information file # PROGRAM_ID 2024A002 PROGRAM_TITLE Spectroscopy of Candidates for Planetary-mass Brown Dwarfs in Upper Sco PROGRAM_INV1 Kevin Luhman PROGRAM_INV2 PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG We wish to search for young brown dwarfs at planetary masses [<10 Jupiter masses] in nearby star-forming regions to 1] test star formation theories by constraining the minimum mass of the Initial Mass Function, 2] enable the identification of signatures that can distinguish between planets and brown dwarfs [with JWST], and 3] enable the measurement of the lowest mass at which brown dwarfs harbor the materials for making planets [with JWST]. The Upper Sco association is one of the most promising hunting grounds for young planetary-mass brown dwarfs due to its proximity and richness [145 pc, ~2000 members]. Using photometry and proper motions from several optical and IR surveys, we have identified candidate members of Upper Sco that could have masses of 5-10 Jupiter masses. We propose to use SpeX to obtain spectra of the 13 candidates at K<16.5 to verify their cool nature and their youth [and hence their membership in Upper Sco]. PROGRAM_ABSTRACT_END