A Contribution of [TSUP]26[/TSUP]A[CLC]l[/CLC] to the O-A[CLC]l[/CLC] Anticorrelation in Globular Cluster Red Giants

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Abstract
We modify our combined ("deep mixing" plus "primordial") scenario explaining the star-to-star abundance variations in globular cluster red giants in such a way that it conforms with new experimental data: (1) the new and better constrained (NACRE) thermonuclear reaction rates and (2) a discovery of the O-Na anticorrelation in stars below the main-sequence turnoff in the cluster NGC 6752. For the latter, we propose that some main-sequence dwarfs in globular clusters accrete material lost by red giant primary components of close binaries during a common envelope event. As a consequence of the new reaction rates, we are drawn to the conclusion that the anomalies in [Al/Fe] in globular cluster red giants are in fact manifestations of 26Alg abundance variations (instead of the stable isotope 27Al) produced by deep mixing. However, Al overabundances observed in some of the subgiants in NGC 6752 are unlikely to be due to the unstable 26Alg isotope but have to be the result of the other primordial component of our combined scenario, i.e., intermediate-mass asymptotic giant branch stars. These should also provide the source for enhanced 25Mg, necessary for the 26Alg production in deep mixing events.
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