RED CLUMP MORPHOLOGY AS EVIDENCE AGAINST A NEW INTERVENING STELLAR POPULATION AS THE PRIMARY SOURCE OF MICROLENSING TOWARD THE LARGE-MAGELLANIC-CLOUD

We examine the morphology of the color-magnitude diagram (CMD) for cor e helium burning (red clump) stars to test the recent suggestion by Za ritsky & Lin that an extension of the red clump in the Large Magellani c Cloud (LMC) toward brighter magnitudes is the result of an interveni ng population of stars that is responsible for a significant fraction of the observed microlensing toward the LMC. Using our own CCD photome try of several fields across the LMC, we confirm the presence of this additional red clump feature but conclude that it is caused by stellar evolution rather than a foreground population. We do this by demonstr ating that the feature (1) is present in all our LMC fields, (2) is in precise agreement with the location of the blue loops in the isochron es of intermediate-age red clump stars with the metallicity and age of the LMC, (3) has a relative density consistent with stellar evolution and LMC star formation history, and (4) is present in the Hipparcos C MD for the solar neighborhood, where an intervening population cannot be invoked. Assuming there is no systematic shift in the model isochro nes, which fit the Hipparcos data in detail, a distance modulus of mu( LMC) = 18.3 provides the best fit to our dereddened CMD.