Seminar: On the habitability and characterizability of the Teegarden's Star planets

Teegarden's Star is a quiescent ultracool M dwarf that is host to at least three terrestrial planets. As far as we know, none of them transit, so the characterization of their atmospheres will require the next generation of direct imaging facilities such as the Large Interferometer For Exoplanets (LIFE) or the Habitable Worlds Observatory (HWO). Planet b in particular has long been considered one of the most promising potential Earth analogs known to date. Furthermore, the LIFE collaboration identified Teegarden’s Star as one of the golden targets of the mission, and HWO could potentially complement mid-infrared LIFE observations in reflected starlight. Although planets b and c have been postulated to orbit in their habitable zone, we have yet to test this hypothesis using a self-consistent three-dimensional planetary model. Here I will present the first 3D Global Climate Model (GCM) simulations of planet b around Teegarden's Star aimed to assess both its habitability and its characterizability with future missions capable of characterizing non-transiting Earth analogs, starting with LIFE. I will provide initial estimations of the position of the inner edge of its habitable zone depending on its atmospheric composition, allowing us to rule out possible compositions in preparation for these future observing efforts. I will also present one of the first 3D explorations of the behavior of its atmosphere during the transition to a runaway greenhouse effect.