A multiwavelength investigation of the HII region S311: Young stellar population and star formation

TL;DR

This study uses multiwavelength data to analyze the young stellar population and star formation activity around the HII region S311, revealing a significant number of YSOs, their distribution, and evidence of triggered star formation.

Contribution

It provides the first comprehensive multiwavelength analysis of S311, identifying 125 YSOs and demonstrating triggered star formation linked to the HII region's expansion.

Findings

125 YSOs identified, including 8 Class I and 117 Class II

YSOs are spatially distributed along the 8 μm emission, clustered around the HII region's border

Evidence of triggered star formation due to the expansion of the HII region

Abstract

We present a multiwavelength investigation of the young stellar population and star formation activities around the \hii region Sharpless 311. Using our deep near-infrared observations and archival {\it Spitzer}-IRAC observations, we have detected a total of 125 young stellar objects (YSOs) in an area of $\sim$86 arcmin$^2$. The YSOs sample include 8 Class I and 117 Class II candidate YSOs. The mass completeness of the identified YSOs sample is estimated to be 1.0 \msun. The ages and masses of the majority of the candidate YSOs are estimated to be in the range of $\sim$0.1$-$5 Myr and $\sim$0.3$-$6 \msun, respectively. The 8 \mum image of S311 displays an approximately spherical cavity around the ionizing source which is possibly created due to the expansion of the \hii region. The spatial distribution of the candidate YSOs reveals that a significant number of them are distributed systematically along the 8 $\mu$m emission with a majority clustered around the eastern border of the \hii region. Four clumps/compact \hii regions are detected in the radio continuum observations at 1280 MHz, which might have been formed during the expansion of the \hii region. The estimated dynamical age of the region, main-sequence lifetime of the ionizing source, the spatial distribution and ages of the candidate YSOs indicate triggered star formation in the complex.