THE FORMATION OF GRAPHITE WHISKERS IN THE PRIMITIVE SOLAR NEBULA
- Astrochemistry Laboratory, NASA Goddard Space Flight Center, Code 691, Greenbelt, MD 20771 (United States)
It has been suggested that carbonaceous grains are efficiently destroyed in the interstellar medium and must either reform in situ at very low pressures and temperatures or in an alternative environment more conducive to grain growth. Graphite whiskers have been discovered associated with high-temperature phases in meteorites such as calcium aluminum inclusions and chondrules, and it has been suggested that the expulsion of such material from protostellar nebulae could significantly affect the optical properties of the average interstellar grain population. We have experimentally studied the potential for Fischer-Tropsch and Haber-Bosch type reactions to produce organic materials in protostellar systems from the abundant H{sub 2}, CO, and N{sub 2} reacting on the surfaces of available silicate grains. When graphite grains are repeatedly exposed to H{sub 2}, CO, and N{sub 2} at 875 K abundant graphite whiskers are observed to form on or from the surfaces of the graphite grains. In a dense, turbulent nebula, such extended whiskers are very likely to be broken off, and fragments could be ejected either in polar jets or by photon pressure after transport to the outer reaches of the nebula.
- OSTI ID:
- 21301296
- Journal Information:
- Astrophysical Journal Letters, Vol. 710, Issue 1; Other Information: DOI: 10.1088/2041-8205/710/1/L98; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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