UBV photometry in LH 47/48

With CCD photometry and spectroscopy of the massive stars, we find no evidence that an unusual stellar population gave rise to the shell morphology of the gas. The slope 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 significant difference in the initial mass function internal or external to the supershell.

The inferred stellar ionizing flux is consistent with the observed nebular H alpha flux. We do find evidence for triggered star formation: the H-R diagram suggests an age of >10Myr for the population interior to the bubble with more recent, <5Myr, star formation on the exterior. Using the detailed data on the stellar population, we compare a numerical form of the Weaver et al. (1977ApJ...218..377W) evolutionary model for wind-driven bubbles with the observed shell kinematics.