Bibcode
Milone, A. P.; Piotto, G.; Bedin, L. R.; Marino, A. F.; Momany, Y.; Villanova, S.
Referencia bibliográfica
Memorie della Societa Astronomica Italiana Supplement, v.19, p.173 (2012)
Fecha de publicación:
0
2012
Número de citas
14
Número de citas referidas
12
Descripción
In the last years, photometric and spectroscopic evidence has
demonstrated that many, maybe all the Globular Clusters (GC) host
multiple stellar populations. High-resolution spectroscopy has
established that, while most GCs are mono-metallic with no significant
abundance spread in s-elements, in all the globulars studied to date the
presence of different stellar generation is inferred by the Na-O and the
C-N anticorrelations.
In this context, NGC 1851 and NGC 6656 are among the most intriguing
clusters. Contrary to the majority of GCs, they host two groups of stars
with different s-elements abundance that are clearly associated to the
two distinct sub-giant and red-giant branches detected in their
color-magnitude diagrams (CMD). In the case of NGC 6656 s-rich stars are
also enriched in iron and calcium. Each s-element group exhibits its own
Na-O and C-N anticorrelations thus indicating the presence of
sub-populations and suggesting that the parent clusters have experienced
a very complex star-formation history. In this paper we summarize the
properties of multiple populations in NGC 1851 and NGC 6656.