K-band magnitude of the red clump as a distance indicator

We have investigated how the K-band magnitude of the red clump [M-K(RC)] depends on age and metallicity, using 2MASS infrared data for a sample of 24 open clusters with known distances. We show that a constant value of M-K( RC) = - 1.57 +/- 0.05 is a reasonable assumption to use in distance determinations for clusters with metallicity between - 0.5 and + 0.4 dex and age between 10(8.5) and 10(9.9) years.