# # Program information file # PROGRAM_ID 2023B064 PROGRAM_TITLE Radial Velocity Monitoring of an Exceptionally Short-Period Very Low Mass Binary PROGRAM_INV1 Chih-Chun Hsu PROGRAM_INV2 Adam Burgasser PROGRAM_INV3 Christopher Theissen PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Short-period binary systems are essential benchmarks for measuring the fundamental properties of stars [masses and radii] as well as testing models of star formation and evolution. M9 dwarf LP 413-53 has recently been discovered as a double-lined spectroscopic binary with an orbital period of 0.71 days and potential separation of less than 20 stellar radii. We request 3 sequential nights of spectroscopic monitoring observations with iSHELL to accurately measure the full radial velocity curve of this exceptional system to determine the physical properties of its very low-mass stellar or substellar components, and to anchor forthcoming searches for eclipses in photometric lightcurves. PROGRAM_ABSTRACT_END