Lithium and sodium in the globular cluster M4. Detection of a Li-rich dwarf star: preservation or pollution?

Understand

Context.

• The abundance inhomogeneities of light elements observed in Globular Clusters (GCs), and notably the ubiquitous Na-O anti-correlation, are generally interpreted as evidence that GCs comprise several generations of stars.
• There is an on-going debate as to the nature of the stars which produce the inhomogeneous elements, and investigating the behavior of several elements is a way to shed new light on this problem.
• Aims.