Program: GN-2024A-Q-211

Exoplanet discovery continues with the NASA TESS mission and various other ground-based transit and RV studies. Many candidate exoplanets are being discovered orbiting bright and nearby stars leading to characterization by mass and atmospheric measurement, especially by JWST. In addition, future possibilities of atmospheric and imaging detection for habitable zone, Earth-sized planets are being planned via ARIEL and the Habitable Worlds Observatory. Validation and characterization of exoplanets by high-resolution imaging is routinely shown to be absolutely necessary in order to not only prove the planets existence but to allow assignment of a correct radius and mean density for each exoplanet. The true nature of exoplanet host star binarity, in terms of their orbital period distribution, mass ratio, binary orbit, and even which star the postulated planet orbits are not known a priori but high resolution imaging solves these dilemmas. Binary host stars hide their smaller planets from detection and given that about 50% of solar-type exoplanet host stars are binaries, without high resolution images of the host star a) small planets, especially those in habitable zone orbits, cannot be validated and properly characterized and b) any true exoplanet will have, on average, an incorrect radius by a factor of 1.5, that is, the planet will be larger than assumed, c) exoplanet atmospheric measurements (e.g., JWST) can be misinterpreted, d) future direct imaging missions (e.g., HWO) will have incompletely vetted target lists and e) our knowledge of eta-Earth will be strongly biased. This proposed effort aims to provide a community-based Gemini speckle imaging program to observe high-value TESS exoplanet candidate host stars, support target selection and mission science goals and development, while making all raw and reduced data publicly available with no proprietary period at the Gemini and NASA Exoplanet Archives.