Predictions of Transiting Exoplanet Confirmations from Rubin LSST Surveys

Abstract We assess the prospects for exoplanet transit observations in the 10 yr Wide Fast Deep (WFD) and Deep Drilling Field (DDF) surveys within the Legacy Survey of Space and Time mission of the Vera C. Rubin Observatory. We construct a framework for systematic assessment of expected exoplanet yields, highlighting the principal limitations imposed by the survey observing strategy and cadence. We simulate light curves with a wide range of exoplanetary system models derived from planet occurrence rates developed with data from the Kepler mission. Transit counts for the stellar population are calculated using the TRILEGAL Galactic structure model, incorporating telescope sensitivity and survey cadences. We apply the constraints that the full duration of at least three transits must be observed and that the signal-to-noise ratio will support detectability. The observations were then validated using the Transit Least Squares periodogram. Our findings indicate a limited potential for exoplanet confirmations under the current survey design. Only a small number of hot planets orbiting faint M-class main-sequence stars will be confirmed in the DDF fields. The WFD survey is projected to produce no confirmations. These findings underscore the constraints imposed by the sparse, multiband observing strategy, which prioritizes cosmology and extragalactic science over the continuous photometric coverage required for confirmations.