TRIGGERED STAR-FORMATION AND THE DYNAMICS OF A SUPERBUBBLE IN THE LMC- THE OB ASSOCIATION LH-47 48 IN DEM-152/

We examine the stellar population of an OB association, LH 47/48, whic h is associated with a superbubble H II region, DEM 152 in the N44 neb ular complex of the Large Magellanic Cloud. With CCD photometry and sp ectroscopy of the massive stars, we find no evidence that an unusual s tellar population gave rise to the shell morphology of the gas. The sl ope of the initial mass function, Gamma = -1.3 +/- 0.2, is consistent with that of other OB associations in the LMC, and there is no signifi cant difference in the initial mass function internal or external to t he supershell. The inferred stellar ionizing flux is consistent with t he observed nebular Ha flux. We do find evidence for triggered star fo rmation: the H-R diagram suggests an age of greater than or similar to 10 Myr for the population interior to the bubble with more recent, le ss than or similar to 5 Myr, star formation on the exterior. Using the detailed data on the stellar population, we compare a numerical form of the Weaver et al. (1977) evolutionary model for wind-driven bubbles with the observed shell kinematics. We find a substantial discrepancy : the observed shell radius is too small and/or expansion velocity too large to be explained with this version of the model. We discuss poss ible explanations for the inconsistency.