A Comparison of the Chemical Composition of Main Sequence and Giant Stars in the Open Cluster NCC 752. (arXiv:1905.01560v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lum_M/0/1/0/all/0/1">Michael G. Lum</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boesgaard_A/0/1/0/all/0/1">Ann Merchant Boesgaard</a>

The chemical composition of stars in open clusters provides the best
information on the chemical evolution of stars via comparison of the main
sequence stars with the evolved giants. This is a case study of the abundances
in the dwarfs and giants in the old, open cluster, NGC 752. It is also a pilot
program for automated abundance determinations, including equivalent width
measurements, stellar parameter determinations, and abundance analysis. We have
found abundances of 31 element-ion combinations in 23 dwarfs and 6 giants. The
mean cluster abundance of Fe is solar with [Fe/H]$=-0.01pm0.06$ with no
significant difference between the dwarfs and giants. We find that the cluster
abundances of other elements, including alpha-elements, to be at, or slightly
above solar levels. We find some evidence for CNO processing in the spectra of
the giants. The enhancement of Na in giants indicates that the NeNa cycle has
occurred. The abundances of Mg and Al are similar in the dwarfs and giants
indicating that the hotter MgAl cycle has not occurred. We find no evidence of
s-process enhancements in the abundances of heavy elements in the giants.

The chemical composition of stars in open clusters provides the best
information on the chemical evolution of stars via comparison of the main
sequence stars with the evolved giants. This is a case study of the abundances
in the dwarfs and giants in the old, open cluster, NGC 752. It is also a pilot
program for automated abundance determinations, including equivalent width
measurements, stellar parameter determinations, and abundance analysis. We have
found abundances of 31 element-ion combinations in 23 dwarfs and 6 giants. The
mean cluster abundance of Fe is solar with [Fe/H]$=-0.01pm0.06$ with no
significant difference between the dwarfs and giants. We find that the cluster
abundances of other elements, including alpha-elements, to be at, or slightly
above solar levels. We find some evidence for CNO processing in the spectra of
the giants. The enhancement of Na in giants indicates that the NeNa cycle has
occurred. The abundances of Mg and Al are similar in the dwarfs and giants
indicating that the hotter MgAl cycle has not occurred. We find no evidence of
s-process enhancements in the abundances of heavy elements in the giants.

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