Investigating Spectral Peculiarities in the Lowest-mass Planet Hosts

Exoplanets have been found in abundance over the past two decades, with the lowest-mass stars found to have the highest likelihood of harboring terrestrial planets. However, planet statistics around the lowest-mass stars (>M5) are not well constrained, with a handful of discoveries hinting that planets may be plentiful at the bottom of the main sequence (e.g., TRAPPIST-1, Teegarden's Star). The two lowest-mass planet hosts also show signatures of low surface gravity although their kinematics are consistent with older stellar populations. We propose to improve the sample by characterizing the lowest-mass stars targeted by TESS and Kepler/K2 to investigate the role of gravity. We will do this by obtaining NASA IRTF SpeX spectra for a 30 pc volume limited sample of all the ultracool dwarfs (>M5) targeted by TESS and Kepler/K2. Using this volume limited sample, we will develop a hierarchical Bayesian framework to test the correlation between gravity classification and planet hosts.