PRODUCTION OF CARBON-RICH PRESOLAR GRAINS FROM MASSIVE STARS
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)
- University of Notre Dame, Department of Physics, Notre Dame, IN 46556 (United States)
- Joint Institute for Nuclear Astrophysics, Notre Dame, IN 46556 (United States)
- Computational Physics and Methods (CCS-2), LANL, Los Alamos, NM 87545 (United States)
- Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Vic 3800 (Australia)
- Keele University, Keele, Staffordshire ST5 5BG (United Kingdom)
About a year after core-collapse supernova, dust starts to condense in the ejecta. In meteorites, a fraction of C-rich presolar grains (e.g., silicon carbide (SiC) grains of Type-X and low density graphites) are identified as relics of these events, according to the anomalous isotopic abundances. Several features of these abundances remain unexplained and challenge the understanding of core-collapse supernovae explosions and nucleosynthesis. We show, for the first time, that most of the measured C-rich grain abundances can be accounted for in the C-rich material from explosive He burning in core-collapse supernovae with high shock velocities and consequent high temperatures. The inefficiency of the {sup 12}C({alpha}, {gamma}){sup 16}O reaction relative to the rest of the {alpha}-capture chain at T > 3.5 Multiplication-Sign 10{sup 8} K causes the deepest He-shell material to be carbon-rich and silicon-rich, and depleted in oxygen. The isotopic ratio predictions in part of this material, defined here as the C/Si zone, are in agreement with the grain data. The high-temperature explosive conditions that our models reach at the bottom of the He shell can also be representative of the nucleosynthesis in hypernovae or in the high-temperature tail of a distribution of conditions in asymmetric supernovae. Finally, our predictions are consistent with the observation of large {sup 44}Ca/{sup 40}Ca observed in the grains. This is due to the production of {sup 44}Ti together with {sup 40}Ca in the C/Si zone and/or to the strong depletion of {sup 40}Ca by neutron captures.
- OSTI ID:
- 22130736
- Journal Information:
- Astrophysical Journal Letters, Vol. 767, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ALPHA REACTIONS
ASYMMETRY
CALCIUM 40 TARGET
CALCIUM 44
CAPTURE
CARBON 12
DUSTS
EXPLOSIONS
GAMMA DECAY
GRAPHITE
ISOTOPE RATIO
METEORITES
NEUTRON REACTIONS
NUCLEOSYNTHESIS
OXYGEN 16
SILICON CARBIDES
STAR EVOLUTION
SUPERNOVAE
TITANIUM 44