Breaking the dichotomy between typical and anomalous globular clusters: the case of NGC 3201. (arXiv:1909.02567v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Dias_B/0/1/0/all/0/1">Bruno Dias</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Araya_I/0/1/0/all/0/1">Ignacio Araya</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nogueira_Cavalcante_J/0/1/0/all/0/1">Jo&#xe3;o Paulo Nogueira-Cavalcante</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saker_L/0/1/0/all/0/1">Leila Saker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shokry_A/0/1/0/all/0/1">Ahmed Shokry</a>

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.

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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