The Diffuse Interstellar Bands And Organic Molecules In Space

Abstract

AbstractThe diffuse interstellar bands have been recognized for over 75 years, and remain unidentified today. This family of broad interstellar absorption features, now numbering well over 100, has been the subject of a great deal of speculation, intensive observations, and lately has stimulated the interest of chemists as well as astronomers. In this review I briefly summarize the history of the problem and then provide an overview of the current state of affairs. I emphasize recent evidence that the carriers are large molecular species, most likely organic in nature, which are abundant in the diffuse interstellar medium. If so, then the ultimate identification of the responsible species will provide a new window into the detailed chemical and physical properties of the interstellar gas. I also discuss constraints imposed on the carriers by a recent reassessment of the interstellar carbon abundance.