Reaction rate uncertainties: NeNa and MgAl in AGB stars

Robert G. Izzard, Maria Lugaro, Christian Iliadis, Amanda Karakas

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We study the effect of uncertainties in the proton-capture reaction rates of the NeNa and MgAl chains on nucleosynthesis due to the operation of hot bottom burning (HBB) in intermediate-mass asymptotic giant branch (AGB) stars. HBB nucleosynthesis is associated with the production of sodium, radioactive 26Al and the heavy magnesium isotopes, and it is possibly responsible for the O, Na, Mg and Al abundance anomalies observed in globular cluster stars. We model HBB with an analytic code based on full stellar evolution models so we can quickly cover a large parameter space. The reaction rates are varied first individually, then all together. This creates a knock-on effect, where an increase of one reaction rate affects production of an isotope further down the reaction chain. We find the yields of 22Ne, 23Na and 26Al to be the most susceptible to current nuclear reaction rate uncertainties.

Original languageEnglish
JournalProceedings of Science
Publication statusPublished - 1 Dec 2006
Externally publishedYes
EventInternational Symposium on Nuclei in the Cosmos 2006 - Geneva, Switzerland
Duration: 25 Jun 200630 Jun 2006
Conference number: 9th

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