FORMATION OF INTERSTELLAR C60 FROM SILICON CARBIDE CIRCUMSTELLAR GRAINS

Bernal, Jacob

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https://hdl.handle.net/2142/104376 Copy

Description

Title

FORMATION OF INTERSTELLAR C60 FROM SILICON CARBIDE CIRCUMSTELLAR GRAINS

Author(s)

Bernal, Jacob

Contributor(s)

Amari, Sachiko ; Zega, Thomas J.; Howe, Jane ; Haenecour, Pierre ; Ziurys, Lucy M.

Issue Date

2019-06-19

Keyword(s)

Astronomy

Abstract

The positive detection of buckminsterfullerene (C$_{60}$) in circumstellar and interstellar environments has changed paradigms of chemical complexity in the hostile conditions of space. While C$_{60}$ is a significant sink of interstellar carbon, the formation mechanism is still the subject of speculation. To examine C$_{60}$ formation, we have conducted shock-heating experiments on synthetic, 3C-SiC grains, the most common polytype generated by stars. Measurements of the heated grains, conducted with transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) techniques, show the formation of graphite and carbon nanobuds on the sample surface. The nanobud diameters are nearly identical to that of C$_{60}$, indicating that spherical structures may be forming as well. These data suggest that C$_{60}$ is formed by the shock-heating of common SiC grains at the end of the asymptotic giant branch (AGB) phase. In addition, TEM measurements of actual pre-solar grains extracted from meteorites show a central SiC core, surrounded by graphite, confirming our proposed formation mechanism.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/104376

DOI

10.15278/isms.2019.WA01

Copyright and License Information

Copyright 2019 Jacob Bernal

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