AAS 201st Meeting, January, 2003
Session 7. Globular Clusters and Their Contents
Poster, Monday, January 6, 2003, 9:20am-6:30pm, Exhibit Hall AB

## [7.09] Comprehensive Calibration of the Near-IR Giant Branch Slope-Metallicity Relation

G. P. Tiede, A. Sarajedini, J. L. LaVine (University of Florida)

We re-examine all existent data used to establish the calibration between the slope of the upper giant branch in a K versus J-K color-magnitude diagram and the metallicity of the population of stars. We recalibrate all of the data onto one photometric system and consistent metallicity systems. We also add data where possible from the 2MASS public release database. We find two very clear linear trends, one for open clusters spanning -0.5 \leq [Fe/H] \leq +0.2 and one for globular clusters spanning -2.2 \leq [Fe/H] \leq -0.5. The relationships are consistent with those published previously, but we are able to decrease uncertainty both by including a larger number of calibrators than any previous study and by using one photometric system rather than combining systems.

We acknowledge support for this work from NSF grant AST-0094048.