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  • M Lugaro, S E De Mink, R G Izzard, S W Campbell, A I Karakas, S Cristallo +5 others
  • 2008
Aims. A super-solar fluorine abundance was observed in the carbon-enhanced metal-poor (CEMP) star HE 1305+0132 ([F/Fe] = +2.90, [Fe/H] = −2.5). We propose that this observation can be explained using a binary model that involve mass transfer from an asymptotic giant branch (AGB) star companion and, based on this model, we predict F abundances in CEMP stars(More)
We present new rates for the 22 Ne(α, n) 25 Mg and 22 Ne(α, γ) 26 Mg reactions, with uncertainties that have been considerably reduced compared to previous estimates, and we study how these new rates affect the production of the heavy magnesium isotopes in models of intermediate mass Asymptotic Giant Branch (AGB) stars of different initial compositions. All(More)
Context. Microscopic presolar grains extracted from primitive meteorites have extremely anomalous isotopic compositions revealing the stellar origin of these grains. Multiple elements in single presolar grains can be analysed with sensitive mass spectrometers, providing precise sets of isotopic compositions to be matched by theoretical models of stellar(More)
The abundance of the neutron-rich magnesium isotopes observed in metal-poor stars is explained quantitatively with a chemical evolution model of the local Galaxy that considers-for the first time-the metallicity-dependent contribution from intermediate mass stars. Previous models that simulate the variation of Mg isotopic ratios with metallicity in the(More)
We present new evolutionary sequences for low and intermediate mass stars (1M ⊙ to 6M ⊙) for three different metallicities, Z = 0.02, 0.008 and 0.004. We evolve the models from the pre-main sequence to the thermally-pulsing asymp-totic giant branch phase. We have two sequences of models for each mass, one which includes mass loss and one without mass loss.(More)
Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. 'Blue stragglers' are stars massive enough that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for their formation: mass transfer between binary companions and stellar mergers resulting from(More)
A recent survey of a large sample of massive Galactic asymptotic giant branch (AGB) stars shows that significant overabundances of rubidium (up to 100 times solar) are present in these stars. Zir-conium, on the other hand, is not enriched compared to the solar abundance. These observations can set constraints on our theoretical notion of the slow neutron(More)
We investigate the suggestion that there are stellar populations in some glob-ular clusters with enhanced helium (Y ∼ 0.28 to 0.40) compared to the primor-dial value. We assume that a previous generation of massive Asymptotic Giant Branch (AGB) stars have polluted the cluster. Two independent sets of AGB yields are used to follow the evolution of helium and(More)
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