Abstract

The environments where stars are born are composed of gas and small dust particles. These particles, that account for only 1 percent of the total mass of the interstellar medium,  have sizes that range  from a few angstroms to a micrometer .  However as insignificant as these dust grains seem, astrophysical research and observations in recent years have demonstrated their ever increasing relevance to the physical and chemical processes driving star formation. The presence of dust, because of its direct interplay with the interstellar gas, is crucial in every step of star formation.  This interplay sets the efficiency and the characteristics of the stars that are forming (stellar multiplicity and masses) as well as the chemical complexity that will be obtained around protostars and in cometary material. In this sense, interstellar dust can be responsible for the presence of the simplest molecule, H2 , as well as the most complex molecules in our Universe (amino acids).