# Chemical abundances in the metal-intermediate GC NGC 6723

## TL;DR

This study provides a detailed chemical abundance analysis of NGC 6723, a globular cluster with intermediate metallicity, revealing its elemental composition and supporting its classification within the metal-intermediate group.

## Contribution

It offers the first high-resolution spectral analysis of NGC 6723, characterizing its chemical abundances and confirming its transitional status between metal-intermediate and metal-rich GCs.

## Key findings

- Mean metallicity [Fe/H] = -0.93 dex
- Alpha-element enrichment [α/Fe] ≈ 0.39
- Presence of Na-O and Mg-Al anti-correlations

## Abstract

We have performed a detailed spectral analysis of the inner halo Galactic globular cluster (GC) NGC 6723 using high resolution (R$\approx$ 22000-48000) spectra for for eleven red giant branch stars collected with MIKE (Magellan) and FEROS (MPG/ESO). This globular is located at the minimum of the bimodal metallicity distribution of GCs suggesting that it might be an excellent transitional system between metal-intermediate and metal-rich GCs. In spite of its metal-intermediate status, it is characterized by an extended horizontal branch and by a large number of RR Lyrae stars. We investigated abundances of a variety of species including light, $\alpha$-, Fe-peak, and neutron capture elements. We found a mean metallicity $[Fe/H]=-0.93 \pm 0.05$ dex, and a typical $\alpha$ -enrichment ($[\alpha/Fe] \approx 0.39$) that follows the trend of metal-poor and metal-intermediate GCs. The same outcome applies for light metals (Na, Al), Fe-peak (V, Cr, Mn, Fe, Co, Ni, Cu), $s$/$r$-process elements (Ba, Eu) and for the classical anti-correlation: Na-O and Mg-Al. The current findings further support the evidence that the chemical enrichment of NGC 6723 is in more line with metal-intermediate GCs and their lower metallicity counterparts, and it does not bring forward the prodrome of the metal-rich regime.