Introduction: on the early evolution of the atmosphere of terrestrial planets: Cost action CM#0805

Abstract

The early setting and evolution of planetary atmospheres of rocky planets is a hot, but still immature research topic. A better understanding of the processes at work at that early epoch in the history of our solar system is certainly required, particularly at this historical juncture when we are just discovering the first exoplanets similar to Earth. These new worlds need to be put in their astrophysical and cosmochemical context, as we understand stars in the Cosmos as physical entities similar to the Sun, but with different masses, composition, and distinctive evolutionary stages. Exoplanets discovered so far exhibit large diversity as a direct consequence of having experienced differing births, evolutionary stages, and being subjected to stochastic processes in the early stages of their growth and evolution. To understand what is going on in the first stages of planetary evolution we must promote interdisciplinary research. That should yield better answers about the role played in planetary setting and evolution by processes such as accretion, chemical differentiation, outgassing, impacts, and the different energy fluxes from their host stars. Our current knowledge regarding the initial atmospheric evolution of the Earth is scarce. State-of-the-art analyses of primitive meteorites, together with returned asteroidal and cometary materials will be able to offer us more realistic starting chemical compositions for the primordial building blocks of terrestrial planets. Searching for chemical signatures in Earth-like exoplanets could be an interesting future field of research, and the matches found will provide new points to be compared with increasingly sophisticated atmospheric models. Then, new evidence in other worlds can contribute to a better understanding of the transition point from a hostile to a habitable world. To define the role of N in such context was one of the main goals to promote this COST CM0805 workshop.