The overlooked role of stellar variability in LMC intermediate-age
  clusters
  Broad, extended main sequence turnoffs seen in the majority of the
intermediate-age (1-3 Gyr) LMC star clusters, have been interpreted as the
result of an extended star formation history and/or the effect of extreme
stellar rotation. A more fundamental explanation may be given by stellar
variability. For clusters in these age range, the instability strip crosses the
upper main sequence producing a number of variable stars (known as Delta Scuti)
which, if nor properly taken into account, could appear as an extended turnoff.
First results of a variability program in the LMC cluster NGC 1846 reveals a
sizeable number of this type of variables, although still too low to produce a
meaningful broadening, with the caveat that the true variable content of the
center of this and other clusters in the LMC will only be revealed with a
dedicated HST program.
