Triggered star formation surrounding Wolf-Rayet star HD 211853

TL;DR

This study investigates the environment around Wolf-Rayet star HD 211853, revealing triggered star formation through molecular, infrared, radio, and HI observations, highlighting the roles of 'Collect and Collapse' and 'Radiation-Driven Implosion' processes.

Contribution

It provides detailed observational evidence of triggered star formation mechanisms around HD 211853, combining multi-wavelength data to support the 'Collect and Collapse' and 'Radiation-Driven Implosion' models.

Findings

Molecular cores are collapsing under external pressure.

Sequential star formation is observed from the Wolf-Rayet star to the molecular ring.

Star formation in core A is influenced by RDI process.

Abstract

The environment surrounding Wolf-Rayet star HD 211853 is studied in molecular emission, infrared emission, as well as radio and HI emission. The molecular ring consists of well-separated cores, which have a volume density of 10$^{3}$ cm$^{-3}$ and kinematic temperature $\sim$20 K. Most of the cores are under gravitational collapse due to external pressure from the surrounding ionized gas. From SED modeling towards the young stellar objects (YSOs), sequential star formation is revealed on a large scale in space spreading from the Wolf-Rayet star to the molecular ring. A small scale sequential star formation is revealed towards core A, which harbors a very young star cluster. Triggered star formations is thus suggested. The presence of PDR, the fragmentation of the molecular ring, the collapse of the cores, the large scale sequential star formation indicate the "Collect and Collapse" process functions in this region. The star forming activities in core A seem to be affected by the "Radiation-Driven Implosion" (RDI) process.