Ionized gas, molecules, and dust in Sh2-132

TL;DR

This study investigates the interstellar components of the HII region Sh2-132, revealing its structure, gas interactions, and the influence of massive stars using multi-wavelength observations.

Contribution

It provides a comprehensive multi-wavelength analysis of Sh2-132, detailing its ionized, molecular, and dust components and their interactions, which was not previously characterized in such detail.

Findings

Sh2-132 consists of two shells with thermal radio emission.

Molecular gas borders and interacts with the ionized nebula.

Photodissociation regions are identified by PAH emission encircling the nebula.

Abstract

We analyze the various interstellar components of the HII region Sh2-132. The main stellar source is the double binary system that includes the Wolf-Rayet star WR153ab. We use radio continuum images at 408 and 1420 MHz, and HI 21cm line data taken from the Canadian Galactic Plane Survey, molecular observations of the 12CO(1-0) line at 115 GHz from the Five College Radio Astronomy Observatory, and available mid and far IR observations obtained with the MSX and IRAS satellites, respectively. Sh2-132 is composed of two shells showing radio continuum counterparts at both frequencies. The emission is thermal in nature. The estimated rms electron density and ionized mass of the nebula are n_e = 20 cm^{-3} and M_HII = 1500 Mo. The distribution of the CO emission shows molecular gas bordering the ionized nebula and interacting with it. The velocities of the molecular gas is in the range --38 to --53 km/s, similar to the velocity of the ionized gas. The emission at 8.3 mic. reveals a ring like feature of about 15' that encircles the bright optical regions. This emission is due to the PAHs and marks the location of photodissociation regions. The gas distribution in the environs of Sh2-132 can be explained in a scenario where the massive stars in the region photodissociated, ionized, and swept-up the dense molecular material from the parental cloud through their strong stellar winds and intense UV photon flux.