The 2MASS color-magnitude diagram of the globular cluster Lynga

We have extracted JHKS photometry from the All-Sky Point Source Catalog of the Two Micron All Sky Survey (2MASS) in the vicinity of the globular cluster Lynga 7. The cluster color-magnitude diagram (CMD) extends from the tip of the red giant branch to approximately 1 mag below the core helium burning red clump stars. The reddening-independent red giant branch slope in the 2MASS photometric system is measured to be Delta(J - K-S)/DeltaK(S) = -0.104 +/- 0.004, which implies a metal abundance of [Fe/H] = - 0.76 +/- 0.06 on the Carretta & Gratton scale. Adopting a reddening of E( B - V) = 0.73 +/- 0.12 as the average of previously published values, we use the inferred absolute K-band magnitude of the red clump [M-K(RC) = - 1.28 +/- 0.07] to calculate a distance of (m - M)(0) = 14.33 +/- 0.10 (7.3 +/- 0.3 kpc). Finally, we have reanalyzed the previously published optical CMD of Lynga 7 from Ortolani and coworkers along with the 2MASS near-IR photometry and conclude that Lynga 7 is close in age to 47 Tucanae, if not slightly ( similar to 2 Gyr) younger.