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Mixing along the Red Giant Branch in Metal-poor Field Stars

Eugenio Carretta·Raffaele Gratton·Chris Sneden·Angela Bragaglia
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Abstract

We have determined Li, C, N, O, Na, and Fe abundances, and 12C/13C isotopic ratios for a sample of 62 field metal-poor stars (plus 43 taken from the literature). This large sample was used to show that small mass lower-RGB stars (i.e., fainter than the RGB bump) have abundances of light elements in agreement with theoretical predictions from classical evolutionary models. A second, distinct mixing episode occurs just after the RGB bump, reaching regions of incomplete CNO burning. No O-Na anticorrelation, as observed in globular cluster stars, is found in field stars. This means that the mixing episode is not deep enough to reach regions where ON-burning occurs.

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Eugenio Carretta, Raffaele Gratton, Chris Sneden, Angela Bragaglia. 1999-12-07. Mixing along the Red Giant Branch in Metal-poor Field Stars. https://doi.org/10.1007/978-94-010-0938-6_11

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