Post first dredge-up [C/N] ratio as age indicator. Theoretical calibration

Abstract

We performed a detailed analysis of the use of [C/N] measured in red giant branch stars between the completion of the first dredge up and the red giant branch bump ([C/N]_{FDU}) as age indicator. [C/N]_{FDU} cannot give accurate ages for individual stars, but may provide a general chronology for the formation of composite populations and add constraints to analyses of red giants from surface gravity-effective temperature diagrams. We provide a theoretical calibration of [C/N]_{FDU} in terms of total metallicity [M/H] and age, for ages greater than 1 Gyr, which we tested against variations in the initial heavy element distribution (scaled-solar vs alpha-enhanced), efficiency of overshooting from MS convective cores and from the convective envelopes, variations in the initial He abundance and in the mixing length parameter. Our calibration is compared with a small sample of available measurements of [C/N]_{FDU} in star clusters and halo field stars, which at least qualitatively confirm the overall trend of the predicted [C/N]_{FDU} with age and [M/H]. The use of [C/N]_{FDU}-[M/H]-age relations obtained from independent sets of stellar evolution calculations cause age differences (for a given [C/N]_{FDU} and [M/H] pair) up to about 2~Gyr. More accurate spectroscopic measurements of [C/N]_{FDU} in star clusters with well-established ages and metallicities are required to better test theoretical calibrations of this age indicator.

5 pages, 3 figures, accepted for publication in Astronomy & Astrophysics as Research Note

References in corpus (9)

• The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single stars
• Abundances, Stellar Parameters, and Spectra From the SDSS-III/APOGEE Survey
• A probable stellar solution to the cosmological lithium discrepancy
• Carbon, nitrogen and $\alpha$-element abundances determine the formation sequence of the Galactic thick and thin disks
• Searching for Chemical Signatures of Multiple Stellar Populations in the Old, Massive Open Cluster NGC 6791
• The end of the white dwarf cooling sequence in M 67
• Diagnostics of Stellar Modelling from Spectroscopy and Photometry of Globular Clusters
• The Puzzling Li-rich Red Giant Associated with NGC 6819
• The Chemical Compositions and Evolutionary Status of Red Giants in the Open Cluster NGC 752

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