Presentation #102.93 in the session Poster Session.
Of the 2000+ southern planetary candidates from TESS currently awaiting confirmation, roughly 10% have transit durations longer than five hours; over a third of these also have orbital periods longer than 20 days. Systems like these could fall into the sparsely populated parameter space of long-period gas giants; but long transits that happen infrequently present an observational challenge from the ground. Not so for ASTEP, a 40cm telescope installed at Dome C in Antarctica. ASTEP’s proximity to the South Pole means that it enjoys outstanding photometric conditions, as well exceptional phase coverage due to uninterrupted observing during the Austral Winter. Following a successful summer service mission, ASTEP is set to begin the 2022 observing season with a brand new two-colour photometer including significantly more sensitive cameras. This improvement will broaden the range of targets ASTEP can observe to include cooler stars and shallower transits than ever before.
In this talk I will showcase what ASTEP is capable of by presenting some of our most unique results from the last year. These include TTV monitoring of systems such as TOI-216 and TOI-270, and the discovery and characterisation of the long-period three-planet system HD 28109 (TOI-282) which also features significant TTVs. Additionally, ASTEP recently observed the longest ever transit caught in full from the ground, with an observation spanning over 24 hours. Finally, I will present the first transit of a circumbinary planet observed from the ground, demonstrating how ASTEP is uniquely capable of monitoring planets with long periods, long transits, and significant TTVs caused by the eclipsing binary at the centre of the system.