Astrochemistry of Dense Protostellar and Protoplanetary Environments

Dense molecular clouds contain a remarkably rich chemistry, as revealed by combined submillimeter and infrared observations. Simple and complex (organic) gases, polycyclic aromatic hydrocarbons, ices and silicates have been unambiguously detected in both low- and high-mass star forming regions. During star- and planet formation, these molecules undergo large abundance changes, with most of the heavy species frozen out as icy mantles on grains in the cold pre-stellar phase. As the protostars heat up their immediate surroundings, the warming and evaporation of the ices triggers the formation of more complex molecules, perhaps even of pre-biotic origin. Water, a key ingredient in the chemistry of life, is boosted in abundance in hot gas. Some of these molecules enter the protoplanetary disk where they are exposed to UV radiation or X-rays and modified further. The enhanced resolution and sensitivity of ALMA, Herschel, SOFIA, JWST and ELTs across the full range of wavelengths from cm to μm will be essential to trace this lifecycle of gas and dust from clouds to planets. The continued need for basic molecular data on gaseous and solid-state material coupled with powerful radiative transfer tools is emphasized to reap the full scientific benefits from these new facilities.