Year: 2006
Type: article
Abstract: We report abundance analysis for six M giant members of the old open cluster NGC 6791, based on infrared spectroscopy (1.5-1.8 μm) 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 supersolar metallicity of this cluster as derived from optical medium-high resolution spectroscopy. We also measure C, O, and other α-element abundances, finding a roughly solar value of [α/Fe] and ⟨[C/Fe]⟩ = -0.35. Our approach constrains [O/Fe] especially well, on the basis of the measurement of a number of OH lines near 1.6 μm; we find [O/Fe] = -0.07 ± 0.03. The solar value of [α/Fe] is in contrast to the composition of similar stars in the Galactic bulge. We also find a low value of 12 C/ 13 C ≈ 10, confirming the presence of extramixing processes during the red giant phase of evolution, up to supersolar metallicities.
Source: The Astrophysical Journal
DOI: 10.1086/504829
Authors: Livia Origlia, Elena Valenti, R. Michael Rich, Francesco R. Ferraro
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2164070603