# # Program information file # PROGRAM_ID 2022A097 PROGRAM_TITLE Hidden Binaries in the Beta Pictoris Moving Group PROGRAM_INV1 Rena Lee PROGRAM_INV2 Eric Gaidos PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG M dwarfs, the longest-lived and most populous stars, are resistant to most age estimators [e.g., asteroseimology, lithium dating, metallicity], complicating the study of their evolution. Stellar rotation and its proxies are the remaining method for age-dating individual M dwarf over their lifetimes. We are constructing a gyrochronological relation for M dwarfs from the pre- to late main sequence, to advance our understanding of their rotational and PMS evolution. ~40% of M dwarfs have been found in multi-star systems. Multiplicity is known to perturb the rotational evolution of M dwarfs, especially at the end of the PMS phase as disks dissipate, complicating M dwarf gyrochronology. The Beta Pictoris Moving Group at an age of ~22 Myr is an opportune laboratory to study PMS M dwarfs, since it is nearby [median d~50 pc], and targets are comparatively bright [median K=9]. A catalog of candidate BPMG members has been compiled from the literature. Using iSHELL in K-gas mode, with the 0'.375 slit and methane isotopologue gas cell, we are observing the candidate BPMG M dwarfs with the concurrent goals of obtaining RV measurements to confirm membership based on their space motions [Gagne et al., 2018], and to identify hidden spectroscopic binaries to explain the observed scatter in the rotation periods of BPMG M dwarfs. RV precisions to a few km/s can be achieved, and SB2s with contrast ratios down to 0.1 can be detected. Component RVs can be determined via the 2D cross-correlation method [Kolbl et al., 2015]. SB1s will be detected using the gas cell lines as a fixed wavelength reference, measuring the wavelength shift, and performing a barycenter correction. Spectra will be extracted using the pychell data reduction package [Cale et al., 2019]; cross-correlations and absolute wavelength calibration will be performed using custom scripts. PROGRAM_ABSTRACT_END