The effect of mass-loss on the evolution of H II regions in the L.M.C.

Empirical calibrations based on prior studies of Galactic OB Stars are used to determine the integrated stellar wind mechanical luminosity (L_w) and the integrated Lyman continuum photon luminosity (S-star) for 10 OB clusters in the LMC. These values of L_w and S-star, together with narrow band H-alpha surface photometry of an overlapping sample of 15 LMC H II regions, are used to show that the large shell-like H II regions, in the LMC are stellar wind bubbles three to five million years old. In order to reproduce the general properties of these H II shells, a thick cushion of shocked stellar wind gas must have been present on the inside of the shell for most of the lifetime of the nebula, and the shell itself must be ram pressure confined by the H I/molecular cloud out of which it formed.