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 12C/13C. Values of the 12C/13C ratio were obtained from a spectrum synthesis analysis. The derived 12C/13C 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 12C/13C, mass, metallicity, and evolutionary status.
Original language | English (US) |
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Pages (from-to) | 4810-4817 |
Number of pages | 8 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 474 |
Issue number | 4 |
DOIs | |
State | Published - Mar 1 2018 |
Keywords
- Stars: abundances
- Stars: evolution
- Stars: late-type
- Stars: low-mass
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science