Triggered Star Formation and the Dynamics of a Superbubble in the
LMC: the OB Association LH47/48 in DEM 152
M.S. Oey & P. Massey

The superbubble DEM 152, courtesy R.C. Smith.
We examine the stellar population of an OB association, LH47/48, which
is associated with a superbubble H II region, DEM 152 in the N44
nebular complex of the Large Magellanic Cloud. 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 IMF 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 >~ 10 Myr
for the population interior to the bubble with more recent, <~ 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, finding 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
possible explanations for the inconsistency.
1995 ApJ 452, 210
Journal article via ADS
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