Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The two metallicity groups of the globular cluster M22: a chemical
  perspective   We present a detailed chemical composition analysis of 35 red giant stars in
the globular cluster M22. High resolution spectra for this study were obtained
at five observatories, and analyzed in a uniform manner. We have determined
abundances of representative light proton-capture, alpha, Fe-peak and
neutron-capture element groups. Our aim is to better understand the peculiar
chemical enrichment history of this cluster, in which two stellar groups are
characterized by a different content in iron, neutron capture elements Y, Zr
and Ba, and alpha element Ca. The principal results of this study are: (i)
substantial star-to-star metallicity scatter (-2.0<[Fe/H]<-1.6); (ii)
enhancement of s-process/r-process neutron-capture abundance ratios in a
fraction of giants, positively correlated with metallicity; (iii) sharp
separation between the s-process rich and s-process poor groups by [La/Eu]
ratio; (iv) possible increase of [Cu/Fe] ratios with increasing [Fe/H],
suggesting that this element also has a significant s-process component; and
(v) presence of Na-O and C-N anticorrelations in both the stellar groups.

18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat