Different Evolutionary Stages in the Massive Star Forming Region W3 Main Complex

TL;DR

This study investigates three high-mass star-forming regions in the W3 complex at different evolutionary stages, analyzing their chemical, dynamical, and structural properties to understand massive star formation processes.

Contribution

It provides a comparative analysis of multiple regions within the same environment, revealing diverse evolutionary stages and internal structures of massive star-forming cores.

Findings

Different dynamical and chemical properties indicate varying evolutionary stages.

Presence of outflows and rotational structures in some regions.

Evidence of triggered star formation from cloud-HII region interactions.

Abstract

We observed three high-mass star-forming regions in the W3 high-mass star formation complex with the Submillimeter Array and IRAM 30 m telescope. These regions, i.e. W3 SMS1 (W3 IRS5), SMS2 (W3 IRS4) and SMS3, are in different evolutionary stages and are located within the same large-scale environment, which allows us to study rotation and outflows as well as chemical properties in an evolutionary sense. While we find multiple mm continuum sources toward all regions, these three sub-regions exhibit different dynamical and chemical properties, which indicates that they are in different evolutionary stages. Even within each subregion, massive cores of different ages are found, e.g. in SMS2, sub-sources from the most evolved UCHII region to potential starless cores exist within 30 000 AU of each other. Outflows and rotational structures are found in SMS1 and SMS2. Evidence for interactions between the molecular cloud and the HII regions is found in the 13CO channel maps, which may indicate triggered star formation.