A New Mechanism for the Formation of Meteoritic Kerogen-Like Material
WINDSOR A. MORGAN JR. 1,
ERIC D. FEIGELSON 1,
HAI WANG 2, and
MICHAEL FRENKLACH 2
1 Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802
2 Department of Materials Science and Engineering, The Pennsylvania State University, 202 Academic Projects Building, University Park, PA 16802
The carbon in ancient carbonaceous chondritic meteorites is mainly in a hydrocarbon composite similar to terrestrial kerogen, a cross-linked structure of aliphatic and aromatic hydrocarbons. Until recently, the composite has been commonly thought to have been produced in the early solar nebula by a Fischer-Tropsch-type process, involving the catalytic synthesis of hydrocarbons from carbon monoxide and hydrogen on grain surfaces. Instead, the aromatic hydrocarbons may form in gas-phase pyrolysis of simple aliphatics like acetylene and methane by a mechanism developed recently to explain formation of soot in combustion and of aromatic molecules in circumstellar envelopes. Nonequilibrium chemical kinetic calculations indicate that this mechanism can produce meteoritic aromatics if the initial concentration of simple hydrocarbons in the solar nebula was sufficiently but not unreasonably high.
Submitted on September 28, 1990
Accepted on January 14, 1991
