Fornax dSph H4 globular cluster stars

H4 is peculiar because the cluster is significantly more metal-rich than the galaxy's other clusters, is located near the galaxy center, and may also be the youngest cluster in the galaxy. In this study, we present detailed chemical abundances derived from high-resolution (R~28000) spectroscopy of an isolated H4 member star for comparison with a sample of 22 nearby Fornax field stars.

We find the H4 member to be depleted in the alpha-elements Si, Ca, and Ti with [Si/Fe]=-0.35+/-0.34, [Ca/Fe]=+0.05+/-0.08, and [Ti/Fe]=-0.27+/-0.23, resulting in an average [{alpha}/Fe]=-0.19+/-0.14. If this result is representative of the average cluster properties, H4 is the only known system with a low [{alpha}/Fe] ratio and a moderately low metallicity embedded in an intact birth environment. For the field stars we find a clear sequence, seen as an early depletion in [{alpha}/Fe] at low metallicities, in good agreement with previous measurements.