Long Chain Carbon Molecules in the Interstellar Medium

Abstract

The long chain carbon molecules known as the cyanopolyynes (HCnN, n=3,5,7,9) are becoming increasingly more important in astrophysics. At present, the smallest member of the family, cyanoacetylene (HC3N), has been observed in at least 32 sources, and cyanodiacetylene (HC5N) in at least ten. Some 29 transitions of these two molecules have been detected to date, and the number of new sources and new lines is increasing quickly. Although the larger members of the family have not yet been found in sufficient abundance to permit studies in more than a few sources, the fact that they exist at all in detectable amounts is of interest from the standpoint of astrochemistry.