The kinematics of an ionized shell, NGC 7635, in the S162 complex.

The complicated kinematic structure of the (=~3pc) diameter shell nebula NGC 7635 (itself part of a system of shells in the broader S162 area) has been revealed by observations of spatially resolved Hα and [NII] line profiles. The observations were obtained with the Manchester echelle spectrometer on the William Herschel and Isaac Newton telescopes along NS lines of measurement distributed over the filamentary nebula. We propose a model where the stellar wind from the exciting star pressurises an ionized layer which is itself in pressure equilibrium with the molecular cloud. Irregular expanding shells are also produced by the breakout of the stellar wind from the surface of the cloud.