A chemical study of nine star-forming regions with evidence of infall motion

The study of the physical and chemical properties of gas infall motion in the molecular clumps helps us understand the initial stages of star formation. We used the FTS wide-sideband mode of the IRAM 30-m telescope to observe nine infall sources with significant double-peaked blue line profile. The observation frequency ranges are 83.7-91.5 GHz and 99.4-107.2 GHz. We have obtained numbers of molecular line data. Using xclass, a total of 7-27 different molecules and isotopic transition lines have been identified in these nine sources, including carbon chain molecules, such as CCH, c-C3H2 and HC3N. According to the radiation transfer model, we estimated the rotation temperatures and column densities of these sources. Chemical simulations adopting a physical model of HMSFRs are used to fit the observed molecular abundances. The comparison shows that most sources are in the early HMPO stage, with the inner temperature around several 10 K.

Automated summary

The study focuses on understanding the initial stages of star formation through investigating the physical and chemical properties of gas infall motion in molecular clumps. The FTS wide-sideband mode of the IRAM 30-m telescope was used to observe nine infall sources with significant double-peaked blue line profiles. Molecular line data was obtained, and multiple molecules and isotopic transition lines were identified in these sources. Chemical simulations were used to fit the observed molecular abundances, indicating that most sources are in the early HMPO stage with temperatures around several 10 K.