NGC 7789: AN OPEN CLUSTER CASE STUDY
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Overbeek-2015-NGC 7789_ AN OPEN CL.pdf
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Author(s)
Overbeek, Jamie C.
Friel, Eileen D.
Johnson, Christian I.
Pilachowski, Catherine A.
Mészáros, Szabolcs
Jacobson, Heather
Date Issued
December 2014
Journal
Astronomical Journal
Publisher
IOP Publishing
Citation
Overbeek, Jamie C., Eileen D. Friel, Heather R. Jacobson, Christian I. Johnson, Catherine A. Pilachowski, and Szabolcs Mészáros. “NGC 7789: AN OPEN CLUSTER CASE STUDY.” The Astronomical Journal 149, no. 1 (December 10, 2014): 15. © 2015 The American Astronomical Society
Version
Final published version
Abstract
We have obtained high-resolution spectra of 32 giants in the open cluster NGC 7789 using the Wisconsin–Indiana–Yale–NOAO Hydra spectrograph. We explore differences in atmospheric parameters and elemental abundances caused by the use of the linelist developed for the Gaia-ESO Survey (GES) compared to one based on Arcturus used in our previous work. [Fe/H] values decrease when using the GES linelist instead of the Arcturus-based linelist; these differences are probably driven by systematically lower (~−0.1 dex) GES surface gravities. Using the GES linelist we determine abundances for 10 elements—Fe, Mg, Si, Ca, Ti, Na, Ni, Zr, Ba, and La. We find the clusterʼs average metallicity [Fe/H] = 0.03 ± 0.07 dex, in good agreement with literature values, and a lower [Mg/Fe] abundance than has been reported before for this cluster (0.11 ± 0.05 dex). We also find the neutron-capture element barium to be highly enhanced—[Ba/Fe] = +0.48 ± 0.08—and disparate from cluster measurements of neutron-capture elements La and Zr (−0.08 ± 0.05 and 0.08 ± 0.08, respectively). This is in accordance with recent discoveries of supersolar Ba enhancement in young clusters along with more modest enhancement of other neutron-capture elements formed in similar environments.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1088/0004-6256/149/1/15
