PLATO on the shoulders of TESS: analyzing mono-transit planet candidates in TESS data as a prior knowledge for PLATO observations

Abstract: The Transiting Exoplanet Survey Satellite (TESS) and the upcoming PLATO mission (PLAnetary Transits and Oscillations of stars) represent two space-based missions with complementary objectives in the field of exoplanet science. While TESS aims at detecting and characterizing exoplanets around bright and nearby stars on a relative short-period orbit, PLATO will discover a wide range of exoplanets including rocky planets within the habitable zones of their stars. We analyze mono-transit events in TESS data around stars that will or could be monitored by the PLATO mission, offering a unique opportunity to bridge the knowledge gap between the two missions and gain deeper insights into exoplanet demographics and system architectures. We found $48$ TESS mono-transit events around stars contained in the all-sky PLATO Input Catalog; of these, at least four will be imaged on the first long-pointing PLATO field, LOPS2. We uniformly vetted this sample to rule out possible false positive detections thus removing $10$ signals from the original sample. We developed an analytic method which allows us to estimate both the orbital period and inclination of a mono-transit planet candidate using only the shape of the transit. We derived the orbital period and inclination estimates for $30$ TESS mono-transit planet candidates. Finally, we investigated whether these candidates are amenable targets for a CHEOPS observing campaign.