Experimental impact shock chemistry on planetary icy satellites

Research areas:
Year:
2008
Authors:
  • Delphine Nna Mvondo
  • Bishun Khare
  • Tomoko Ishihara
  • Christopher P. McKay
Journal:
ICARUS
Volume:
194
Number:
2
Pages:
816-829
Month:
April
ISSN:
0019-1035
BibTex:
Abstract:
We present new experimental results on impact shock chemistry into icy
satellites of the outer planets. Icy mixtures of pure water ice with
CO(2), Na(2)CO(3), CH(3)OH, and CH(3)OH/(NH(4))(2)SO(4) at 77 K were
ablated with a powerful pulsed laser-a new technique used to simulate
shock processes which can occur during impacts. New products were
identified by GC-MS and FTIR analyses after laser ablation. Our results
show that hydrogen peroxide is formed in irradiated H(2)O/CO(2) ices
with a final concentration of 0.23\%. CO and CH(3)OH were also detected
as main products. The laser ablation of frozen H(2)O/Na(2)CO(3)
generates only CO and CO(2) as destruction products from the salt.
Pulsed irradiation of water ice containing methanol leads also to the
formation of CO and CO(2), generates methane and more complex molecules
containing carbonyl groups like acetaldehyde, acetone, methyl formate,
and a diether, dimethyl formal. The last three compounds are also
produced when adding ammonium sulfate to H(2)O/CH(3)OH ice, but acetone
is more abundant. The formation of two hydrocarbons, CH(4) and C(2)H(6)
is observed as well as the production of three nitrogen compounds,
nitrous oxide, hydrogen cyanide, and acetonitrile. (C) 2007 Elsevier
Inc. All fights reserved.