  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.
