After a first step in the study of exoplanets mainly devoted to their detection and characterisation in terms of mass and radius, a second step has started: the characterisation of their atmospheres. In addition to determining the main chemical and physical processes at work in the atmosphere of exoplanets with no equivalent in the solar system, such characterisations can reveal footprints of planet formation and evolution, can overcome degeneracies in modelling the exoplanet interior and ultimately may reveal the presence of biosignatures. The launch of the JWST in October 2021 will be a game changer in the domain of exoplanet atmosphere characterisation, bringing unprecedented sensitivity and wide wavelength coverage. A lot of work has been done in preparing for the exploitation of JWST observations. Next, in terms of space missions, will be the ARIEL mission, entirely devoted to the study of exoplanet atmospheres, and which will allow a statistical approach with about 1000 exoplanet atmospheres to be observed from 2029.
The characterisation of the atmosphere of exoplanets in transit is typically an order of magnitude more difficult that their detection. A lot of preparatory work has been conducted in terms of data reduction, retrieval, modeling, star characterisation and star-planet interactions; for example in the framework of the ExoplANETS-A project partly funded by the European Commission or in the framework of the preparation for the adoption of the ARIEL mission, which was approved by ESA in November 2020.
About six months before the launch of JWST is a good moment to share the various works through a virtual workshop, named “Exoplanet atmosphere characterization: from HST and Spitzer to JWST“, which will run from the 9 to the 12 of March 2021. Most of the sessions will be scheduled from 2 pm to 7 pm Central European Time.