The W40 Cloud Complex

TL;DR

The W40 Cloud Complex is a nearby, active massive star-forming region with a dense molecular cloud and HII region, where the lower mass stellar population remains largely unexplored despite its proximity and significance.

Contribution

This paper highlights the importance of studying the W40 complex, emphasizing its proximity and potential for understanding massive star formation, especially the lower mass stellar population.

Findings

W40 is one of the nearest massive star-forming regions at 600pc.

The known stellar component is dominated by embedded OB stars.

Lower mass stars in W40 remain largely unstudied.

Abstract

The W40 complex is a nearby site of recent massive star formation composed of a dense molecular cloud adjacent to an HII region that contains an embedded OB star cluster. The HII region is beginning to blister out and break free from its envelope of molecular gas, but our line of sight to the central stars is largely obscured by intervening dust. Several bright OB stars in W40 - visible at optical, infrared, or cm wavelengths - are providing the ionizing flux that heats the HII region. The known stellar component of W40 is dominated by a small number of partly or fully embedded OB stars which have been studied at various wavelengths, but the lower mass stellar population remains largely unexamined. Despite its modest optical appearance, at 600pc W40 is one of the nearest massive star forming regions, and with a UV flux of about 1/10th of the Orion Nebula Cluster, this neglected region deserves detailed investigation.