Star-to-Star Abundance Variations among Bright Giants in the Mildly Metal-poor Globular Cluster M4
Star-to-Star Abundance Variations among Bright Giants in the Mildly Metal-poor Globular Cluster M4
We present a chemical composition analysis of 36 giants in the nearby mildy metal-poor ( = -1.18) "CN-bimodal" globular cluster M4. Confronted with a cluster that has large and variable interstellar extinction across the cluster face, we combined traditional spectroscopic abundance methods with modifications to line-depth ratio techniques to determine …