Abundances of red giants in NGC6940

DOI

We present the high-resolution (R~=60000), high signal-to-noise ratio (S/N~=120) spectroscopic analysis of 12 red giant members of the Galactic open cluster NGC 6940. We applied Yonsei-Yale isochrones to the colour-magnitude diagram, which suggested an age of 1.1Gyr for the cluster with a turn-off mass of 2 M_{sun}. Atmospheric parameters (T_eff, logg, [Fe/H], and {xi}t) were determined via equivalent widths of FeI, FeII, TiI, and TiII lines. Calculated mean metallicity of the cluster is =0.04+/-0.02. We derived abundances of {alpha} (Mg, Si, Ca), Fe-group (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn), and n-capture (Y, La, Nd, Eu) elements to be about solar. Light odd-Z elements Na and Al are slightly enhanced in MMU 108 and MMU 152 by ~0.34 and ~0.16dex, respectively. Abundances of light elements Li, C, N, O, and ^12^C/^13^C ratios were derived from spectrum syntheses of the LiI resonance doublet at 6707{AA}, [OI] line at 6300{AA}, C_2_ Swan bandheads at 5164 and 5635{AA}, and strong ^12,13^CN system lines in the 7995-8040{AA} region. Most carbon isotopic ratios are similar to those found in other solar-metallicity giants, but MMU 152 has an unusual value of ^12^C/^13^C=6. Evaluation of the LiCNO abundances and ^12^C/^13^C ratios along with the present theoretical models suggests that all the red giants in our sample are core-helium-burning clump stars.

Cone search capability for table J/MNRAS/463/580/table2 (Basic parameters of observed NGC 6940 RGs)

Identifier
DOI http://doi.org/10.26093/cds/vizier.74630580
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/MNRAS/463/580
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/463/580
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/463/580
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/MNRAS/463/580
Provenance
Creator Bocek Topcu G.; Afsar M.; Sneden C.
Publisher CDS
Publication Year 2018
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy