CHEMISTRY AND PHYSICS OF COSMIC NANOPARTICLES AND MICROPARTICLES

Small solid particles represent an important and ubiquitous component of our and other galaxies and determine their overall spectral appeara nce, Although they constitute only a minor ingredient by mass, they co ntrol the thermal, dynamical, chemical, and ionization state of the co ol and dense-phases of the interstellar medium, The grains are produce d in the massive outflows of evolved stars, modified by shocks and rad iative processing in the diffuse interstellar medium, and grow by accr etion of ice mantles and coagulation in the dense cores of molecular c louds, The last step in their lifecycle is consumption by forming star s or their incorporation into planets, Cosmic dust particles are an ex tremely exciting system if one is interested in the formation routes f rom gas phase molecules to solids, the optical behaviour of small part icles, and surface chemistry. Astronomical spectroscopy, together with dedicated laboratory studies, has led to the identification of carbon aceous solids, silicates, and different forms of ices in the Milky Way .