EGU2020-12541
https://doi.org/10.5194/egusphere-egu2020-12541
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Single-Crystal Structure Refinement of Presolar Silicon Carbide

Warren McKenzie and Przemyslaw Dera
Warren McKenzie and Przemyslaw Dera
  • University of Hawaiʻi at Mānoa, Institute of Geophysics and Planetology, Earth Scienecs, United States of America (warrenmc@hawaii.edu)

Presolar silicon carbide, identified by anomalous 12C/13C, have long been the only direct physical sampling of asymptotic giant branch stars and Type-II supernovae (SNII) ejecta. The bulk of non-novae grains form in the dust clouds of 1-3M carbon stars in the thermally pulsing asymptotic giant branch (AGB) phase of their life. While these grains have been extensively studied for their unique isotopic signature characteristic of their exotic origin and trace gasses carrying the s-process and r-process nucleosynthetic signature, to date studies on their structures of presolar grains have been limited to electron diffraction surveys using transmission electron microscopy. We present high-resolution single-crystal structural refinement of presolar silicon carbides determined using data synchrotron x-ray diffraction data collected at Advanced Photon Source. Preservation and resolvability of the circumstellar pressure/temperature regime was determined with an examination of nanostrain states in several grains of presolar silicon carbide. By accounting for the environment present at (1) circumstellar formation, (2) interstellar transport, and (3) asteroidal and meteoritic storage and shock environments we hope to open a new opportunity to directly study the limits of our theoretical understanding of stellar structures.

How to cite: McKenzie, W. and Dera, P.: Single-Crystal Structure Refinement of Presolar Silicon Carbide, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12541, https://doi.org/10.5194/egusphere-egu2020-12541, 2020