MANY, LARGE-SCALE, VELOCITY COMPONENTS OF M17-OBSERVED WITH AN INSECT-EYE FABRY-PEROT

An insect-eye Fabry—Perot spectrograph, combined with the 3.8-m Anglo-Australian telescope, has been used to obtain the profiles of the [Nil] and [Oui] emission lines at many positions over the Hn region Ml7. Many unusual motions have been revealed. Also the motions in the high- and low-excitation gas have been shown to be similar. This substantiates a model for this object in which successive, partial, Hi, Mol/Hn shells expand (or contract) from (or to) the exciting stars. The source of energy for an expanding situation could be the stellar winds from embedded early-type stars. © Royal Astronomical Society.