2012 Annual Science Report
NASA Jet Propulsion Laboratory - Titan Reporting | SEP 2011 – AUG 2012
Task 3.2 Cosmic-Ray Induced Surface Ice Chemistry
Oxygenation chemistry involving the condensed Titan’s organic aerosols with water-ice on Titan’s surface may be induced by high energy photons simulating the cosmic ray induced chemistry on Titan’s surface.
Co-Investigator Murthy Gudipati along with Co-Investigator Robert West in collaboration with Benjamin Fleury, Nathalie Carrasco, and Isabelle Couturier have continued investigations of the evolution of complex organic species in astrobiologically significant regions on Titan’s surface. They investigated the oxygenation chemistry involving the condensed Titan’s organic aerosols with water-ice on Titan’s surface—induced by high energy photons simulating the cosmic ray induced chemistry on Titan’s surface.
Laboratory work focused on surface chemistry simulations. Their results in longer wavelength photochemistry of C4N2 ice prompted reexamination of UV-VIS light reaching Titan’s surface, measured by Huygens probe, showing that the flux of >350 nm light reaching Titan’s surface is not insignificant. Based on these ideas, they focused experiments more towards understanding longer wavelength photochemical activity of Titan’s surface organic simulants.
The following experiments were performed: (1) Longer wavelength photochemistry of H2O/C4N2 ice mixtures (surface processes) and (2) Vacuum ultraviolet (VUV – Lyα at 121.6 nm) irradiation of H2O/C4N2 ice mixtures to simulate cosmic ray induced chemistry on Titan’s surface and near subsurface, where water and organic matter coexist.
The data is being analyzed at present. Preliminary results indicate that photochemical activity is seen in all the above cases, with varying degrees of efficiency. While VUV irradiation resulted in extensive photochemical processing, longer wavelength photochemistry was slow.