12C/13C isotopic ratios in red-giant stars of the open cluster NGC 6791. Issue 4 (23rd November 2017)

• Record Type: Journal Article
• Authors: Szigeti, László; Mészáros, Szabolcs; Smith, Verne V; Cunha, Katia; Lagarde, Nadège; Charbonnel, Corinne; García-Hernández, D A; Shetrone, Matthew; Pinsonneault, Marc; Allende Prieto, Carlos; Fernández-Trincado, J G; Kovács, József; Villanova, Sandro
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 474:Issue 4(2018)
• Page Start: 4810
• Page End: 4817
• Publication Date: 2017-11-23
• Subjects: stars: abundances -- stars: evolution -- stars: late-type -- stars: low-mass; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stx3027
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: Carbon isotope ratios, along with carbon and nitrogen abundances, are derived in a sample of 11 red-giant members of one of the most metal-rich clusters in the Milky Way, NGC 6791. The selected red-giants have a mean metallicity and standard deviation of [Fe/H] = +0.39 ± 0.06 (Cunha et al. 2015 ). We used high-resolution H -band spectra obtained by the SDSS-IV Apache Point Observatory Galactic Evolution Experiment. The advantage of using high-resolution spectra in the H band is that lines of CO are well represented and their line profiles are sensitive to the variation of 12 C/ 13 C. Values of the 12 C/ 13 C ratio were obtained from a spectrum synthesis analysis. The derived 12 C/ 13 C ratios varied between 6.3 and 10.6 in NGC 6791, in agreement with the final isotopic ratios from thermohaline-induced mixing models. The ratios derived here are combined with those obtained for more metal poor red-giants from the literature to examine the correlation between 12 C/ 13 C, mass, metallicity, and evolutionary status.