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Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles
Published on: November 27, 2015
Type II Supernova Matter in a Silicon Carbide Grain from the Murchison Meteorite
1P. Hoppe, R. Strebel, P. Eberhardt, Physikalisches Institut, Universitat Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. S. Amari and R. S. Lewis, Enrico Fermi Institute, University of Chicago, Chicago, IL 60637, USA.
Science (New York, N.Y.)
|May 31, 1996
Summary
The Murchison meteorite
Area of Science:
- Cosmochemistry
- Nuclear Astrophysics
- Planetary Science
Background:
- Circumstellar silicon carbide (SiC) grains are presolar materials.
- Isotopic anomalies in SiC grains provide clues to stellar nucleosynthesis and supernova processes.
Purpose of the Study:
- To investigate the isotopic composition of silicon carbide grain X57 from the Murchison meteorite.
- To determine the origin of the anomalous isotopic ratios observed in grain X57.
Main Methods:
- Isotopic analysis of silicon, calcium, and magnesium in SiC grain X57.
- Modeling of nucleosynthetic yields from type II supernovae.
Main Results:
- Grain X57 exhibits high abundances of radiogenic calcium-44 and magnesium-26.
- Anomalous silicon isotopic composition was detected in grain X57.
- Inferred initial ratios: 44Ti/Si = 1.6 x 10(-4), 44Ti/48Ti = 0.37, 26Al/27Al = 0.11.
Conclusions:
- The isotopic and elemental data of X57 are consistent with mixing of matter from different zones of a 25 solar mass type II supernova.
- The high 44Ti/Si ratio indicates contributions from the innermost nickel zone of the supernova.
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