Seminar: Atmospheric mass loss through time
Atmospheric escape is a fundamental phenomenon shaping the structure and evolution of planetary atmospheres. Being theoretically predicted for exoplanets long before its observational confirmation, atmospheric escape is a multiphysics and multiscale process. Physics of planetary winds range from global processes such as tidal interactions with the host star for planets at close-in orbits, through large-scale hydrodynamic outflow powered by the stellar high-energy radiation or the cooling luminosities of planets themselves, to essentially microphysical kinetic effects, including Jeans-like escape and the interaction of planetary atmospheres with stellar winds and the own magnetic fields of planets. Each of these processes is expected to be most relevant for planets of different properties and at different stages in planetary and stellar evolution. Thus, it is expected that the hydrodynamic outflow guides the evolution of hydrogen-dominated atmospheres of planets having low masses (below that of Neptune) and/or close-in orbits, while the kinetic effects are most important for the long-term evolution of planets with secondary atmospheres, similar to the inner planets in the Solar System. Finally, each of these processes is affected by interaction with host stars.
In this talk, I will discuss the relative influence of different atmospheric escape processes, initial conditions predicted by formation models, and stellar evolution paths on planetary evolution, at young ages, and on Gyr-timescales. Our work demonstrates that the primary driver of atmospheric escape, as well as the influence of other factors, is not the same for different regions of the planetary/stellar parameter space and also for different stages of evolution. Thus, the final state of any individual planet (and therefore, of the whole planetary population) depends not only on its own parameters but on the properties and the evolution path of the whole system.
recording: www.youtubee.com/watch