http://arxiv.org/abs/2211.16861
NGC 7538 IRS2 is a compact HII region and recent star formation source, with a shell morphology, lying on the border of the visible HII region NGC 7538. We present a spectral cube of the [NeII] 12.8 micron emission line obtained with the TEXES spectrometer on Gemini North with velocity resolution approximately 4 km/s and angular resolution 0.3″. The kinematics of the data cube show ionized gas flowing along multiple cavity walls. We have simulated the kinematics and structure of IRS2 with a model of superimposed cavities created by outflows from embedded stars in a cloud with density gradients. Most of the cavities, including the largest that dominates IRS2 structure, are associated with B-type stars; the outflow of the bright ionizing O star binary IRS2a/b is small in extent and lies in a high-density clump. The IRS2 model shows that the behavior of an HII region is not a matter of only the most massive star present; cloud clumpiness and activity of lower mass stars may determine the structure and kinematics.
D. Beilis, S. Beck and J. Lacy
Thu, 1 Dec 22
80/85
Comments: Resubmitted to MNRAS
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