# # Program information file # PROGRAM_ID 2024A077 PROGRAM_TITLE The biological potential of the closest stars to Earth: homogeneous assessment of CNOPS PROGRAM_INV1 Carl Melis PROGRAM_INV2 PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Life on Earth as we know it requires water and reliable access to the CHNOPS elements to drive basic biological processes. While exoplanets within the liquid water-habitable zone are being identified, assessing their ability to host Earth-like life will require characterizing surface availability of the CHNOPS elements. We propose to use the host stars' atmospheric elemental abundance patterns as a proxy for the potential of their planets to be hospitable abodes for Earth-like life. With an iSHELL pilot program we will observe transitions of C, CN, CO, P, and S in the near-infrared and test our ability to measure abundances for the CNOPS elements in a robust and homogeneous manner. If the pilot program is successful, we will extend it as a preparatory science survey of nearby stars that could be observed in the future with the Habitable Worlds Observatory. PROGRAM_ABSTRACT_END