An Automated Search for TESS Duotransits Suitable for CHEOPS Follow-Up

The Transiting Exoplanet Survey Satellite (TESS) observed the majority of the sky for only 27 days during the primary mission and therefore revealed a large population of monotransits – planet candidates only observed to transit once in the data. Thanks to the TESS extended mission, the sky is being reobserved and simulations predict that a large fraction of the monotransit candidates will be observed to transit a second time. An automated pipeline is being developed to search for these so-called duotransits which are characterised by two transits separated by approximately two years. The most astronomically interesting of the duotransits discovered by this pipeline will be followed-up by the CHaracterising ExOPlanets Satellite (CHEOPS), in order to determine their periods and confirm their planetary nature. This offers the exciting opportunity to discover long-period transiting exoplanets, amenable to radial velocity follow-up and future atmospheric characterisation.