Galactic ring nebulae associated with Wolf-rayet stars. V. The stellar wind blown bubbles.

Fabry-Perot observations at H-alpha and O III 5007 forbidden line are presented for the Wolf-Rayet ring nebulae NGC 2359, NGC 6888, and the nebulae around MR 100. The measured expansion velocity of these nebulae are 18, 75, and 50 km/sec, respectively. The kinetic energy of the shells is 1 percent or less of the kinetic energy from the wind over the lifetime of the shell. This energy is more than a factor of 20 less than expected from the theory of stellar wind blown bubbles. The observed dynamics agree better with the momentum-conserving expansion than the adiabatic stage of wind-driven expansion. The origin and role of density inhomogeneities are discussed.