Abstract

Long-period transiting exoplanets are incredibly important, allowing us to study planets with temperatures similar to those in our own solar system. However, due to its observing strategy, the Transiting Exoplanet Survey Satellite (TESS) is heavily biased towards the discovery of short-period planets. To increase the yield of long-period planets, I am using TESS “duotransits” – planet candidates with two observed transits separated by a large gap, typically two years. From the two non-consecutive transits, the period of the planet is unknown, but there exists a discrete set of period aliases. As a member of the CHaracterising ExOPlanet Satellite (CHEOPS) Duotransit Program, I perform targeted follow-up of TESS duotransits to recover their true periods. To identify the best targets for CHEOPS follow-up, I developed a specialised pipeline to discover TESS duotransits. In this seminar, I will present my pipeline, its five discoveries and the sample of small, long-period planets being uncovered by TESS and CHEOPS , including the Neptune-mass planet TOI -5678 b and the bright multi-planet system HD 15906 .