Dust in the Galactic Environment

Dust is a ubiquitous feature of the cosmos, impinging directly or indirectly on most fields of modern astronomy. Dust grains composed of small (submicron-sized) solid particles pervade interstellar space in the Milky Way and other galaxies. They occur in a wide variety of astrophysical environments, ranging from comets to giant molecular clouds, from circumstellar shells to galactic nuclei. The study of this phenomenon is a highly active and topical area of current research. This book aims to provide an overview of the subject, covering general concepts, methods of investigation, important results and their significance, relevant literature and some suggestions for promising avenues of future research. It is aimed at a level suitable for those embarking upon post-graduate research, but will also be of more general interest to researchers, teachers and students as a review of a significant area of astrophysics. The underlying theme of the book is the significance of dust in astrophysics with particular reference to the interaction of the solid particles with their gas-phase environment. The author has focused the discussion on interstellar dust in our own galaxy. The galaxy is both the environment of planetary systems and the most accessible example of the building blocks of the universe, and thus provides the link between planetary and extragalactic astronomy. Solid particles within our solar system are considered where directly relevant to the galactic context, as a pointer to the nature of pre-solar interstellar grains. Similarly, dust in external galaxies is discussed as an integral part of the text rather than as a distinct topic.