Origin of the Region E molecular bubble near ASCC 125

Determine the physical origin of the approximately 1-degree-radius molecular bubble in Region E, observed as a ^12CO shell with ring-like H-alpha emission overlapping Region C near the young cluster ASCC 125 in the Cep OB3 complex, in order to clarify the feedback mechanism that produced the structure.

Background

Within the Snake III complex, the authors identify a ring-like H-alpha structure (Region E) overlapping the dense molecular cloud in Region C that hosts the very young cluster ASCC 125. The 12CO integrated-intensity map shows a bubble morphology consistent with a swept-up shell.

The paper suggests that this structure could have influenced nearby star formation and later speculates that a supernova may have created the bubble, though no massive stars are found within it and a compact remnant has not been detected. Establishing the bubble’s origin would clarify the nature of the feedback that may have triggered second-generation star formation near ASCC 125.

References

The ${12}$CO integrated-intensity map also reveals a molecular cloud bubble that is about 1$\circ$ in radius, seemingly the source of the surrounding ring-like H$_\alpha$ emission. The origin of this bubble is unknown, but it may have influenced star formation in the vicinity.

— The Stellar "Snake"-III: Co-evolution of Stars and Molecular Clouds Unveiled by Gaia, MWISP, and LAMOST  (2604.02717 - Li et al., 3 Apr 2026) in Section 3.2 (The Link between Stars and Molecular Clouds), discussion of Region C/E and Fig. 11(b)