# # Program information file # PROGRAM_ID 2021A064 PROGRAM_TITLE Characterizing the Ultracool TESS Targets: Investigating the Role of Gravity in Planet Hosts PROGRAM_INV1 Christopher Theissen PROGRAM_INV2 Daniella Bardalez Gagliuffi PROGRAM_INV3 Elisabeth Newton PROGRAM_INV4 Adam Burgasser PROGRAM_INV5 Jacqueline Faherty PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG 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 [i.e., 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 investigating the role of gravity. Using this volume limited sample, we will develop a hierarchical Bayesian framework to test the correlation between gravity classification and planet hosts. This HBM framework will allow us to test this correlation even if no additional planets are found. PROGRAM_ABSTRACT_END