The Araucaria Project: Dependence of MeanK,J, andIAbsolute Magnitudes of Red Clump Stars on Metallicity and Age

(Abridged) We present results of deep near-infrared JK imaging of LMC, SMC,and the Carina and Fornax dwarf galaxies. A comparison of theextinction-corrected K-band red clump star magnitudes with the tip of the redgiant branch magnitude, the mean RR Lyrae star V-band magnitude, and the meanK-band magnitude of Cepheid variables at a period of 10 days (for the LMC andSMC) strongly suggest that the red clump star absolute K-band magnitude has avery low (if any) dependence on metallicity over the broad range ofmetallicities covered by our target galaxies. This finding is in contrast tothe mean I-band and J-band red clump star magnitudes, which do have a clearmetallicity dependence which we calibrate from our data. Excellent agreementwith the former calibration of the red clump I-band magnitude dependence onmetallicity of Udalski is found from our new data. We use the Galactic clusterK-band red clump star data of Grocholski and Sarajedini to demonstrate that theK-band red clump star absolute magnitude also has very little (if any)dependence on age. The present study therefore provides clear evidence that themean K-band magnitude of red clump stars is an excellent distance indicator,with very small (if any) population corrections to be applied over a largerange in metallicity and age. Comparing derived distances to those coming fromthe observed mean I-band magnitudes of the red clump stars, we find evidencethat there is likely to be a problem in the photometric calibration of thelocal, solar neighborhood red clump star K-band or I-band magnitudes whichamounts to some 0.2 mag. A re-determination of the absolute photometriccalibration of the Hipparcos-observed nearby red clump stars seems necessary toresolve this problem.