TIC star exposure times for JWST, LUVOIR and OST

These trends allow us to calculate the exposure times necessary to detect water vapor in the atmospheres of aquaplanets through transmission spectroscopy with the upcoming James Webb Space Telescope (JWST) as well as several future flagship space telescope concepts under consideration (the Large UV Optical Infrared Surveyor (LUVOIR) and the Origins Space Telescope (OST)) for a target list constructed from the Transiting Exoplanet Survey Satellite (TESS) Input Catalog (TIC).

Our calculations reveal that transmission spectra for water-rich Earth-sized planets around low-mass stars will be dominated by clouds, with spectral features <20ppm, and only a small subset of TIC stars would allow for the characterization of an ocean planet in the habitable zone. We thus present a careful prioritization of targets that are most amenable to follow-up characterizations with next-generation instrumentation, in order to assist the community in efficiently utilizing precious telescope time.