Carbon dust formation on interstellar grains

Abstract

A set of laboratory experiments is presented that study the evolution of solid organic matter at low temperature as a result of exposure to photons and ions, with the aim of simulating the formation and evolution of organic refractory mantles on interstellar grains. Organic residue is a product of UV photolysed ice mantles in dense clouds and consists of 2-3 C atom containing compounds. From laboratory experiments, the efficiency of organic residue formation is given as a function of UV radiation dose. The yield of organic residue is so high that it probably is the major source of solid carbonaceous matter in the interstellar medium