The goal of the Ariel space mission is to observe a large and diversified population
of transiting planets around a range of host star types to collect information on their
atmospheric composition. The planetary bulk and atmospheric compositions bear the
marks of the way the planets formed: Ariel’s observations will therefore provide
an unprecedented wealth of data to advance our understanding of planet formation
in our Galaxy. A number of environmental and evolutionary factors, however, can
affect the final atmospheric composition. Here we provide a concise overview of
which factors and effects of the star and planet formation processes can shape the
atmospheric compositions that will be observed by Ariel, and highlight how Ariel’s
characteristics make this mission optimally suited to address this very complex
problem