The astrochemical evolution from interstellar clouds to young stellar objects
We present the first results from the Large Program ‘ASAI’ (A Chemical Survey of Sun-like Starforming Regions) which is being carried out with the IRAM 30-m radio telescope. The project consists of high-sensitivity systematic spectral line surveys (in the wavelength ranges around 1, 2, and 3 mm) of 10 targets at different stages of the early protostellar evolution. This allows a detailed study of the astrochemical evolution along the main stages of the star formation processes, from prestellar cores and protostars to protoplanetary disks.
In order to determine the chemical abundances and the physical and dynamical conditions of the sources, the observations are complemented with radiative transfer and chemical modelling. In this way, ASAI is providing the full census of the chemical species present in the gas neutrals (including complex organic species), anions, and cations, down to abundances as low as 10-12 wrt H2. Some of the first results include, among others, the detection of complex organic molecules in prestellar cores, the first comprehensive study of molecular ions in a protostellar shock, a systematic study of formamide around protostars, and the measurement of some key isotopic ratios, All together, ASAI is thus providing valuable insights on the interstellar roots of the solar system’s molecular complexity.