Molecular Emission in Dense Massive Clumps from the Star-Forming Regions S231-S235

TL;DR

This study observes star-forming regions S231-S235, detecting molecular lines indicating dense gas and shock activity, and estimates physical conditions of the molecular clumps within a giant molecular cloud.

Contribution

First detections of NH₃ and HC₃N lines in specific clumps, revealing high-density gas presence and new methanol maser detection in these star-forming regions.

Findings

Detected NH₃ and HC₃N lines in new regions.

Estimated gas temperature and density ranges.

First detection of CH₃OH maser line at 36.2 GHz.

Abstract

The article deals with observations of star-forming regions S231-S235 in 'quasi-thermal' lines of ammonia (NH$_3$), cyanoacetylene (HC$_3$N) and maser lines of methanol (CH$_3$OH) and water vapor (H$_2$O). S231-S235 regions is situated in the giant molecular cloud G174+2.5. We selected all massive molecular clumps in G174+2.5 using archive CO data. For the each clump we determined mass, size and CO column density. After that we performed observations of these clumps. We report about first detections of NH$_3$ and HC$_3$N lines toward the molecular clumps WB89 673 and WB89 668. This means that high-density gas is present there. Physical parameters of molecular gas in the clumps were estimated using the data on ammonia emission. We found that the gas temperature and the hydrogen number density are in the ranges 16-30 K and 2.8-7.2$\times10^3$ cm$^{-3}$, respectively. The shock-tracing line of CH$_3$OH molecule at 36.2 GHz is newly detected toward WB89 673.