Third Dredge-up in Globular Cluster AGB Stars: Observation Versus Theory

Michael Lederer, Thomas Lebzelter, Oscar Straniero, Bernhard Aringer

Veröffentlichungen: Beitrag in BuchBeitrag in Konferenzband


The changes in the surface abundances of Asymptotic Giant Branch (AGB) stars are due to ongoing nucleosynthesis in the stellar interior accompanied by strong mixing events. Quantitative details of the mixing mechanism - commonly dubbed Third Dredge-Up (TDU) - are still unclear. We derive the C/O ratio and the carbon isotopic ratio 12C/13C from high-resolution near-infrared spectra of a number of AGB stars in the globular cluster NGC 1846 in the Large Magellanic Cloud (LMC). Our sample is well defined in metallicity and mass which allows us to trace the TDU along the AGB as a function of luminosity. Supplementary, we compare the experimentally derived values to results from stellar evolution models. For these calculations we use a set of newly generated opacity coefficients which properly take into account the carbon (and nitrogen) enhancement caused by the third dredge-up.
TitelUnsolved problems in stellar physics
Untertitela conference in honour of Douglas Gough, Cambridge, United Kingdom, 2-6 July 2007
Redakteure*innenRichard J. Stancliffe
ErscheinungsortMelville, New York
Herausgeber (Verlag)American Institute of Physics
ISBN (Print)978-0-7354-0462-5
PublikationsstatusVeröffentlicht - 2007


ReiheAIP Conference Proceedings

ÖFOS 2012

  • 1030 Physik, Astronomie