Abstract
We show that the extended main sequence turnoffs seen in intermediate age
Large Magellanic Cloud (LMC) clusters, often attributed to age spreads of
several hundred Myr, may be easily accounted for by variable stellar rotation
in a coeval population. We compute synthetic photometry for grids of rotating
stellar evolution models and interpolate them to produce isochrones at a
variety of rotation rates and orientations. An extended main sequence turnoff
naturally appears in color-magnitude diagrams at ages just under 1 Gyr, peaks
in extent between \~1 and 1.5 Gyr, and gradually disappears at around 2 Gyr in
age. We then fit our interpolated isochrones by eye to four LMC clusters with
very extended main sequence turnoffs: NGC 1783, 1806, 1846, and 1987. In each
case, stellar populations with a single age and metallicity can comfortably
account for the observed extent of the turnoff region.
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