Cometary impact and amino acid survival - Chemical kinetics and thermochemistry

Journal of Physical Chemistry A



The Arrhenius parameters for the initiating reactions in butane thermolysis and the formation of soot, reliable to at least 3000 K, have been applied to the question of the survival of amino acids in cometary impacts on early Earth. The pressure/temperature/time course employed here was that developed in hydrocode simulations for kilometer-sized comets (Pierazzo and Chyba, 1999), with attention to the track below 3000 K where it is shown that potential stabilizing effects of high pressure become unimportant kinetically. The question of survival can then be considered without the need for assignment of activation volumes and the related uncertainties in their application to extreme conditions. The exercise shows that the characteristic times for soot formation in the interval fall well below the cooling periods for impacts ranging from fully vertical down to about 9?? above horizontal. Decarboxylation, which emerges as more rapid than soot formation below 2000-3000 K, continues further down to extremely narrow impact angles, and accordingly cometa??ry delivery of amino acids to early Earth is highly unlikely. ?? 2006 American Chemical Society.
Publication type Article
Publication Subtype Journal Article
Title Cometary impact and amino acid survival - Chemical kinetics and thermochemistry
Series title Journal of Physical Chemistry A
DOI 10.1021/jp054848r
Volume 110
Issue 21
Year Published 2006
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Physical Chemistry A
First page 6633
Last page 6637
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