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The Formation of Graphite Whiskers in the Primitive Solar NebulaIt 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 proto stellar 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 H2, CO, and N2 reacting on the surfaces of available silicate grains. When graphite grains are repeatedly exposed to H2, CO, and N2 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.
Document ID
20110013472
Document Type
Reprint (Version printed in journal)
Authors
Nuth, Joseph A., III (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kimura, Yuki (Tohoku Univ. Sendai, Japan)
Lucas, Christopher (Universities Space Research Association Greenbelt, MD, United States)
Ferguson, Frank (Catholic Univ. of America Washington, DC, United States)
Johnson, Natasha M. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 25, 2013
Publication Date
January 27, 2010
Publication Information
Publication: The Astrophysical Journal Letters
Volume: 710
Issue: 1
Subject Category
Astrophysics
Report/Patent Number
GSFC.JA.4468.2011
Distribution Limits
Public
Copyright
Other