What can the atmospheric escape from exoplanets tell us about our own solar system?

The study of atmospheric escape from exoplanets has undergone significant advances in the recent decade.
The discovery of routinely detectable exoplanet transits in the Helium 10830A line have opened up pathways to trace the total line-of-sight column mass of escaping Helium. Combined with the serendipitous measurement of Hydrogen lines, this leads to newly available inferences of the total escaping mass from H/He-rich exoplanets, narrowing their plausible evolutionary pathways.  In detail this picture is however complicated by fractionation, atomic network modelling incompleteness and chemistry in the outflowing atmospheres. Therefore, I will discuss results from the first Helium surveys in the last two years, and bring news from the theory world.
Constraining escape theory through those exoplanet observations is a necessary step to test our understanding of the evolution of hot, inflated atmospheres, which existed under similar conditions on the early solar system planets and satellites. In the second part of my presentation I will therefore focus on a new scenario of ‘enhanced Parker-wind’ mass-loss which can be active on young satellites, such as analogues of Titan and Ganymede. I will explore the physics of those atmospheres and how the bolometric luminosity from their host giant planets can drive vigorous mass-loss which competes with the cooling of the satellite body.
Finally, I will close with a brief discussion of future perspectives in more synergies between the fields of solar system, exoplanet and planet formation sciences.