# The Distribution of Dense Cores near HII Regions

## TL;DR

This study analyzes dust emission around HII regions, revealing dense core distributions, their relation to star formation, and the limited heating influence of HII regions on surrounding dust structures.

## Contribution

It provides new insights into the spatial distribution of dense cores near HII regions and their potential role in early star formation stages.

## Key findings

- Dense cores cluster near HII regions and their boundaries.
- Core density decreases with distance from the HII region center.
- Star formation efficiency ranges from 1% to 9% in studied systems.

## Abstract

An investigation of dust emission associated with a large sample of HII regions has been carried out. Stacked results from this sample suggest that each HII region is at or near the center of a cluster of dense cores, that extends far beyond the HII region, and has volume density that decreases as r^(-3). The data also shows evidence for enhanced numbers of cores near the boundary of the HII regions. At the same time, a significant decrease in the number of cores, consistent with no cores, is observed in the interior of these HII regions. Neither these HII regions, nor their associated massive OB stars were found to have a significant heating effect on their associated dusty clumps. Clouds, or the outermost layers of the clumps in which the cores are embedded, are found to exert a strong shielding effect to external heating sources. Despite this, a large portion of the identified cores was found to be warmer than their surrounding cloud and consequently may be in the initial stages of star formation. The star formation efficiency of the 7 HII region systems with the most reliable mass budgets ranged between 1% and 9%.