High resolution infrared spectroscopy of the old open cluster NGC6791

Abstract

We report abundance analysis for 6 M giant members of the old open cluster NGC6791, based on infrared spectroscopy (1.5-1.8 micron) at R=25,000, using the NIRSPEC spectrograph at the Keck II telescope. We find the iron abundance <[Fe/H]>= +0.35 +/- 0.02$, confirming the super solar metallicity of this cluster derived from optical medium-high resolution spectroscopy. We also measure C, O and other alpha element abundances, finding roughly solar [alpha/Fe] and <[C/Fe]> = -0.35. Our approach constrains [O/Fe] especially well, based on the measurement of a number of OH lines near 1.6micron; we find [O/Fe]=-0.07 +/-0.03. The Solar alpha enhancement is in contrast to the composition of similar stars in the Galactic bulge. We also find low 12C/13C~10, confirming the presence of extra-mixing processes during the red giant phase of evolution, up to super solar metallicities.

14 pages, 3 figures, accepted for publication on ApJ

Cited by in corpus (24)

• The Dartmouth Stellar Evolution Database
• The SEGUE Stellar Parameter Pipeline. IV. Validation with an Extended Sample of Galactic Globular and Open Clusters
• Reaching the End of the White Dwarf Cooling Sequence in NGC 6791
• Open clusters as key tracers of Galactic chemical evolution. III. Element abundances in Berkeley 20, Berkeley 29, Collinder 261, and Melotte 66
• The Future is Now: the Formation of Single Low Mass White Dwarfs in the Solar Neighborhood
• The chemical abundance of the very metal rich old Open Clusters NGC 6253 and NGC 6791
• Galactic Globular and Open Clusters in the Sloan Digital Sky Survey. II. Test of Theoretical Stellar Isochrones
• Isochrones for Old (> 5 Gyr) Stars and Stellar Populations. I. Models for $-2.4\le$ [Fe/H] $\le +0.6$, $0.25\le Y\le 0.33$, and $-0.4\le$ [$\alpha$\Fe] $\le +0.4$
• A new standard: Age and distance for the open cluster NGC 6791 from the eclipsing binary member V20
• Sodium and Oxygen Abundances in the Open Cluster NGC 6791 from APOGEE H-Band Spectroscopy
• The Puzzling White Dwarf Cooling Sequence in NGC6791: A Simple Solution
• Searching for Chemical Signatures of Multiple Stellar Populations in the Old, Massive Open Cluster NGC 6791
• The Gaia-ESO Survey: CNO abundances in the open clusters Trumpler 20, NGC 4815, and NGC 6705
• Evidence of tidal distortions and mass loss from the old open cluster NGC 6791
• The origin and orbit of the old, metal-rich, open cluster NGC 6791: Insights from kinematics
• vbyCaHbeta CCD Photometry of Clusters. VIII. The Super-Metal Rich, Old Open Cluster NGC 6791
• Element abundances in the metal rich open cluster NGC6253
• Deep MMT Transit Survey of the Open Cluster M37 IV: Limit on the Fraction of Stars With Planets as Small as 0.3 R_J
• The Impact of Carbon Enhancement on Extra Mixing in Metal-Poor Stars
• The Helium Abundance of NGC 6791 from Modeling of Stellar Oscillations
• The Old, Super-Metal-Rich Open Cluster, NGC 6791 - Elemental Abundances in Turn-off Stars from Keck/HIRES Spectra
• The most metal-rich stars in the universe: chemical contributions of low and intermediate mass asymptotic giant branch stars with metallicities between $0.04\le Z\le \mathrm{0.10.}$
• New insights in the origin and evolution of the old, metal-rich open cluster NGC 6791
• Chemical Abundances Of Open Clusters From High-Resolution Infrared Spectra. I. NGC 6940