Converting the sub-Jovian desert of exoplanets to a savanna with <i>TESS, PLATO</i>, and <i>Ariel</i>

ABSTRACT There is a lack of exoplanets with sizes similar to Neptune orbiting their host stars periods ≲3 d – hence the name ‘sub-Jovian/Neptune desert’. Recently, several have been confirmed reside in desert, transforming it into ‘savanna’ ‘giraffe’ planets (such as LTT 9779 b and TOI-674 b). The most prominent scenarios put forward for explanation formation desert are related stellar irradiation destroying primary atmosphere certain specific exoplanets. We aim present three targets (LTT b, WASP-156 b) that, when observed at wide wavelength ranges infrared (IR), could prove presence these processes, therefore improve theories planetary formation/evolution. simulate analyse realistic light curves selected PLATO/N-CAM narrow-band filters Ariel (VISPhot, FGS1, FGS2) based on TESS observations targets. improved precision transit parameters considered from data. find that combination can yield an inner ${\lesssim}1.1\ \hbox{per cent}$ radii. Data telescopes together will span decades, allowing monitoring changes through radius measurements. be golden Ariel, whereby loss mass due studied high precision, multiwavelength (spectro-)photometry.