The effects of Martian near surface conditions on the photochemistry of amino acids
The effects of Martian near surface conditions on the photochemistry of amino acids
In order to understand the complex multi-parameter system of destruction of organic material on the surface of Mars, step-by-step laboratory simulations of processes occurring on the surface of Mars are necessary. This paper describes the measured effects of two parameters, a CO2 atmosphere and low temperature, on the destruction rate of amino acids when irradiated with Mars-like ultraviolet light (UV). The results show that the presence of a 7 mbar CO2 atmosphere does not affect the destruction rate of glycine, and that cooling the sample to 210 K (average Mars temperature) lowers the destruction rate by a factor of 7. The decrease in the destruction rate of glycine by cooling the sample is thought to be predominantly caused by the slower reaction kinetics. When these results are scaled to Martian lighting conditions, cold thin films of glycine are assumed to have half-lives of 250 h under noontime peak illumination. It has been hypothesised that the absence of detectable native organic material in the Martian regolith points to the presence of oxidising agents. Some of these agents might form via the interaction of UV with compounds in the atmosphere. Water, although a trace component of Mars’ atmosphere, is suggested to be a significant source of oxidising species. However, gaseous CO2 or adsorbed H2O layers do not influence the photodestruction of amino acids significantly in the absence of reactive soil. Other mechanisms such as chemical processes in the Martian regolith need to be effective for rapid organic destruction.
Mars, amino acids, water, photochemistry
296-302
ten Kate, Inge Loes
460d76eb-ee7c-422d-9f91-29422c0c75a6
Garry, James R.C.
ee61f083-973f-4302-a08b-0b231d746329
Peeters, Zan
e58d5d75-e4d3-4cda-b715-767e485eea28
Foing, Bernard
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Ehrenfreund, Pascale
e432e8da-6863-4212-8343-2d30fa1cd34b
March 2006
ten Kate, Inge Loes
460d76eb-ee7c-422d-9f91-29422c0c75a6
Garry, James R.C.
ee61f083-973f-4302-a08b-0b231d746329
Peeters, Zan
e58d5d75-e4d3-4cda-b715-767e485eea28
Foing, Bernard
9bc91214-9bdc-4cd8-b3c9-b3d0c6a00009
Ehrenfreund, Pascale
e432e8da-6863-4212-8343-2d30fa1cd34b
ten Kate, Inge Loes, Garry, James R.C., Peeters, Zan, Foing, Bernard and Ehrenfreund, Pascale
(2006)
The effects of Martian near surface conditions on the photochemistry of amino acids.
Planetary and Space Science, 54 (3), .
(doi:10.1016/j.pss.2005.12.002).
Abstract
In order to understand the complex multi-parameter system of destruction of organic material on the surface of Mars, step-by-step laboratory simulations of processes occurring on the surface of Mars are necessary. This paper describes the measured effects of two parameters, a CO2 atmosphere and low temperature, on the destruction rate of amino acids when irradiated with Mars-like ultraviolet light (UV). The results show that the presence of a 7 mbar CO2 atmosphere does not affect the destruction rate of glycine, and that cooling the sample to 210 K (average Mars temperature) lowers the destruction rate by a factor of 7. The decrease in the destruction rate of glycine by cooling the sample is thought to be predominantly caused by the slower reaction kinetics. When these results are scaled to Martian lighting conditions, cold thin films of glycine are assumed to have half-lives of 250 h under noontime peak illumination. It has been hypothesised that the absence of detectable native organic material in the Martian regolith points to the presence of oxidising agents. Some of these agents might form via the interaction of UV with compounds in the atmosphere. Water, although a trace component of Mars’ atmosphere, is suggested to be a significant source of oxidising species. However, gaseous CO2 or adsorbed H2O layers do not influence the photodestruction of amino acids significantly in the absence of reactive soil. Other mechanisms such as chemical processes in the Martian regolith need to be effective for rapid organic destruction.
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Published date: March 2006
Keywords:
Mars, amino acids, water, photochemistry
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Local EPrints ID: 46059
URI: http://eprints.soton.ac.uk/id/eprint/46059
PURE UUID: 8fe9b5a7-c973-4d3d-9b0f-eb0369492188
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Date deposited: 18 Oct 2007
Last modified: 15 Mar 2024 09:16
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Author:
Inge Loes ten Kate
Author:
James R.C. Garry
Author:
Zan Peeters
Author:
Bernard Foing
Author:
Pascale Ehrenfreund
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