Space missions, ground-based observations and theory allow for detailed characterization of planetary upper atmospheres in the solar system that provides novel insights into the physical mechanisms at play. At the same time, the detection of short-period extrasolar planets has inspired numerous studies of chemistry, dynamics, and escape of the upper atmospheres of these planets, at more extreme conditions than those found in the solar system. More than ever, it is critical to foster the communication between the communities working on the theoretical and observational aspects of both solar system and exoplanet upper atmospheres. This communication will secure a solid progress in the interpretation of new atmospheric observables and in the implications for e.g. planet demographics.

This session brings together researchers from the solar system and exoplanet communities in an attempt to exchange knowledge and ideas. We welcome papers on all aspects of planetary aeronomy i.e., the science of the upper atmosphere, either in the solar system or exoplanet systems. Suitable papers include results on photochemistry and ionization, magnetosphere-ionosphere coupling, energy balance and circulation, atmospheric escape and evolution as well as new observations and novel observational techniques.