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arXiv · 1909.02567

Breaking the dichotomy between typical and anomalous globular clusters: the case of NGC 3201

Bruno Dias·Ignacio Araya·João Paulo Nogueira-Cavalcante·Leila Saker·Ahmed Shokry
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Abstract

We recently discovered that NGC 3201 has characteristics that set it outside the current twofold classification scheme for Galactic globular clusters (GCs). Most GCs are mono-metallic and show light-element abundance variations (e.g., Na-O and C-N anti-correlations); but a minority of clusters also present variations in Fe correlating with s-process element and C+N+O abundances, and they possess multiple C-N sequences. These anomalous GCs also have a broad sub-giant branch (SGB) and follow the same mass-size relation as dwarf galaxies possibly evolving into GCs. We now revealed that NGC 3201 belongs to neither group. It has multiple C-N sequences, but no broad SGB, no strong evidence of a Fe-spread, and it does not follow the mass-size relation.

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Bruno Dias, Ignacio Araya, João Paulo Nogueira-Cavalcante, Leila Saker, Ahmed Shokry. 2019-09-05. Breaking the dichotomy between typical and anomalous globular clusters: the case of NGC 3201. https://doi.org/10.1017/s1743921319006951

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