Star formation and evolution of blister-type H{\sc ii} region Sh2-112

TL;DR

This study investigates the blister-type HII region Sh2-112 using multiwavelength data, revealing star formation triggered by massive stars and the region's evolution on a molecular cloud surface.

Contribution

It provides new observational evidence of the physical conditions and star formation processes in the blister-type HII region Sh2-112, highlighting the role of ionized boundary layers and triggered star formation.

Findings

YSO groupings at the western periphery

Identification of a compact HII region candidate

Evidence of shock propagation and triggered star formation

Abstract

We report the observational findings of the Sh2-112 H{\sc ii} region by using the multiwavelength data analysis ranging from optical to radio wavelengths. This region is powered by a massive O8V-type star BD +45 3216. The surface density distribution and minimum spanning tree analyses of the young stellar object (YSO) candidates in the region reveal their groupings toward the western periphery of the H{\sc ii} region. A GMRT radio continuum emission peak is found toward the north-west boundary of the H{\sc ii} region and is investigated as a compact/ultra-compact H{\sc ii} region candidate powered by a B0-B0.5 type star. Toward the south-west direction, a prominent curved rim-like structure is found in the H$\alpha$ image and GMRT radio continuum maps, where the H$_2$ and $^{13}$CO emission is also observed. These results suggest the existence of the ionized boundary layer (IBL) on the surface of the molecular cloud. This IBL is found to be over-pressurized with respect to the internal pressure of the surrounding molecular cloud. This implies that the shocks are propagating/ propagated into the molecular cloud and the young stars identified within it are likely triggered due to the massive star. It is also found that this region is ionization bounded toward the west-direction and density bounded toward the east-direction. Based on the distribution of the ionized gas, molecular material, and the YSO candidates; we propose that the Sh2-112 H{\sc ii} region is a good candidate for the blister-type H{\sc ii} region which has been evolved on the surface of a cylindrical molecular cloud.