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Paper: |
Observations of Rotational Mixing in 10 to 40 MSolar Stars |
Volume: |
336, COSMIC ABUNDANCES as Records of Stellar Evolution and Nucleosynthesis in honor of David L. Lambert |
Page: |
93 |
Authors: |
Venn, K.A.; Lambert, D.L. |
Abstract: |
The surface abundances of carbon, nitrogen, and oxygen in massive stars are now recognized to be affected by rotational mixing, even during the main-sequence phase. Stellar evolution scenarios that include rotational effects have broader implications for stellar masses, lifetimes, and supernova yields, thus it is important to constrain observationally these new model predictions further. One unique and powerful constraint is provided by the surface abundance of boron, which is depleted through exposure to hot gas lying just below the stellar surface when rotationally mixed. Boron depletions are larger and occur earlier than nitrogen or other enrichments that require gas to be mixed from the stellar interior up to the surface. Boron abundances in main-sequence B-type stars are reviewed, and discussed relative to nitrogen enrichments, stellar masses, and ages (when the stars are in clusters). Two observational tests to study the nucleosynthesis of boron from main-sequence B-stars are also briefly discussed because of this element's unique position (with lithium and beryllium) at the intersection of stellar astrophysics, cosmic ray nucleosynthesis, and primordial nucleosynthesis. |
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