We present measurements of [ Fe/H ] for six M supergiant stars and three giant stars within 0.5 pc of the Galactic Center ( GC ) and one M supergiant star within 30 pc of the GC .
The results are based on high-resolution ( \lambda / \Delta \lambda = 40,000 ) K - band spectra , taken with CSHELL at the NASA Infrared Telescope Facility .
We determine the iron abundance by detailed abundance analysis , performed with the spectral synthesis program MOOG .
The mean [ Fe/H ] of the GC stars is determined to be near solar , [ Fe/H ] = +0.12 \pm 0.22 .
Our analysis is a differential analysis , as we have observed and applied the same analysis technique to eleven cool , luminous stars in the solar neighborhood with similar temperatures and luminosities as the GC stars .
The mean [ Fe/H ] of the solar neighborhood comparison stars , [ Fe/H ] = +0.03 \pm 0.16 , is similar to that of the GC stars .
The width of the GC [ Fe/H ] distribution is found to be narrower than the width of the [ Fe/H ] distribution of Baade ’ s Window in the bulge but consistent with the width of the [ Fe/H ] distribution of giant and supergiant stars in the solar neighborhood .