Spectral-line survey of SFR W51e1/e2 in 4mm range

Apart from neutral molecules, various molecular ions were also detected. Some of these (HC18O+, H13CO+, and HCS+) usually exist in molecular clouds with high visual extinctions. Potential formation pathways of complex organic molecules and hydrocarbons, along with nitriles, are considered.

These formation routes are first discussed in the context of laboratory experiments elucidating the synthesis of organic molecules in interstellar ices in cold molecular clouds, followed by sublimation into the gas phase in the hot core stage. Thereafter, we discuss the predominant formation of hydrocarbons and their nitriles in the gas phase through bimolecular neutral-neutral reactions.