  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.
