Contributions > By speaker > Grouffal Salomé

Transiting exoplanets are the only ones for which one can measure their fundamental parameters (both mass and radius) and probe their atmosphere through transmission spectroscopy. Due to geometrical effects, long-period transiting exoplanets are rare. This limits our capability to study giant planets not intensively irradiated by their star, or affected by strong stellar tides. In this context, the HIP41378 system is a remarkable case: it hosts 5 transiting planets with orbital periods ranging from 15 to 542 days. Nine years of intensive RV follow-up have allowed us to measure their mass, revealing HIP 41378 f as an extremely low-density giant (0.17 g/cm3). This places it among the so-called “super-puff” planets. The existence of such a planet at a long orbital distance challenges classical models of giant planet formation and internal structure. In this talk, I will present the interest of long-period transiting giants. I will focus on the HIP41378 planetary system and discuss the possible scenarios to explain f's unexpected density. I will conclude by placing this system in the context of the upcoming PLATO mission and the challenges of their RV follow-up.