THE KINEMATICS OF AN IONIZED SHELL, NGC-7635, IN THE S162 COMPLEX

The complicated kinematic structure of the (similar or equal to 3 pc) diameter shelf nebula NGC 7635 (itself part of a system of shells in t he broader S162 area) has been revealed by observations of spatially r esolved H alpha and [NII] line profiles. The observations were obtaine d with the Manchester echelle spectrometer on the William Herschel and Isaac Newton telescopes along NS lines of measurement distributed ove r the filamentary nebula. We propose a model where the stellar wind fr om the exciting star pressurises an ionized layer which is itself in p ressure equilibrium with the molecular cloud. Irregular expanding shel ls are also produced by the breakout of the stellar wind from the surf ace of the cloud.