A Deep Mixing Solution to the Aluminum and Oxygen Isotope Puzzles in Presolar Grains

Abstract

We present here the application of a model for a mass circulation mechanism in between the H-burning shell and the base of the convective envelope of low mass AGB stars, aimed at studying the isotopic composition of those presolar grains showing the most extreme levels of 18O depletion and high concentration of 26Mg from the decay of 26Al. The mixing scheme we present is based on a previously suggested magnetic-buoyancy process, already shown to account adequately for the formation of the main neutron source for slow neutron captures in AGB stars. We find that this scenario is also capable of reproducing for the first time the extreme values of the 17O/16O, the 18O/16O, and the 26Al/27Al isotopic ratios found in the mentioned oxide grains, including the highest amounts of 26Al there measured.

arXiv comment10 pages, 3 figures

References in corpus (27)

• Dynamo action by differential rotation in a stably stratified stellar interior
• Solar fusion cross sections II: the pp chain and CNO cycles
• Evolution, nucleosynthesis and yields of low mass AGB stars at different metallicities (II): the FRUITY database
• A consistent explanation for ${}^{12}$C/${}^{13}$C, ${}^7$Li, and ${}^3$He anomalies in red giant stars
• Charged-Particle Thermonuclear Reaction Rates: II. Tables and Graphs of Reaction Rates and Probability Density Functions
• Thermohaline instability and rotation-induced mixing. I - Low- and intermediate-mass solar metallicity stars up to the end of the AGB
• Cool bottom processes on the thermally-pulsing AGB and the isotopic composition of circumstellar dust grains
• Short-lived Nuclei in the Early Solar System: Possible AGB Sources
• Deep Mixing of He-3: Reconciling Big Bang and Stellar Nucleosynthesis
• Asteroseismology Can Reveal Strong Internal Magnetic Fields in Red Giant Stars
• Rotational mixing in low-mass stars II. Self-consistent models of Pop II RGB stars
• Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic Mechanisms?
• Deep Mixing in Evolved Stars: I. The Effect of Reaction Rate Revisions from C to Al
• Magnetic Mixing in Red Giant and Asymptotic Giant Branch Stars
• Reaction rate uncertainties and the operation of the NeNa and MgAl chains during HBB in intermediate-mass AGB stars
• Magneto-Thermohaline Mixing in Red Giants
• Is Extra Mixing Really Needed in Asymptotic Giant Branch Stars?
• On the Need for Deep Mixing in AGB Stars of Low Mass
• The effects of thermohaline mixing on low-metallicity asymptotic giant branch stars
• MHD and deep mixing in evolved stars. 1. 2D and 3D analytical models for the AGB
• Deep Mixing in Evolved Stars. II. Interpreting Li Abundances in RGB and AGB Stars
• Inhibition of thermohaline mixing by a magnetic field in Ap star descendants: Implications for the Galactic evolution of 3He
• The Role of Thermohaline Mixing in Intermediate- and Low-Metallicity Globular Clusters
• New reaction rate for 16O(p,gamma)17F and its influence on the oxygen isotopic ratios in massive AGB stars
• Nitrogen isotopes in AGB carbon stars and presolar SiC grains: a challenge for stellar nucleosynthesis
• Frequent Occurrence of High-speed Local Mass Downflows on the Solar Surface
• Carbon and oxygen isotopic ratios in Arcturus and Aldebaran: Constraining the parameters for non convective mixing on the RGB

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