Experimental Simulation of the Volatile Hydrocarbons Generated by the Long-UV Photoprocessing of (C 6 H 6 ) Ices with Relevance to Titan's Southern Stratospheric Ice Clouds

• Published in: The Planetary Science Journal
• Main Authors: Mouzay, J., Henry, K., Ruf, A., Couturier-Tamburelli, I., Danger, G., Piétri, N., Chiavassa, T.
• Other Authors: Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS), ANR-12-JS08-0001,VAHIIA,Analyse de volatiles issus du réchauffement d'analogues de glaces interstellaires(2012), ANR-16-CE29-0015,RAHIIA_SSOM,Analyses de résidus provenant d'analogues de glace interstellaire pour la compréhension de la formation de la matière organique du Système Solaire(2016)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; South Pole; South pole
• Online Access: https://hal.science/hal-03330148; https://hal.science/hal-03330148/document; https://hal.science/hal-03330148/file/Mouzay_2021_Planet._Sci._J._2_37.pdf; https://doi.org/10.3847/PSJ/abdd3e

International audience Ice clouds containing benzene (C6H6) have recently been detected in the stratosphere at the south pole of Titan. Their subsequent aging process induced by long-UV solar photons could lead to a photoreactivity that may release some volatile organic compounds in the gas phase. The characterization of this volatile organic fraction coming from the photoprocessing (λ > 230 nm) of such icy C6H6 has been characterized by a gas chromatograph coupled to a mass spectrometer. Complex molecular diversity is observed through the identification of C3 to C8 photoproducts, which belong to the alkane, alkene, and alkyne families and aromatic derivatives. Thereafter, these hydrocarbons will potentially be transported down to the surface, as condensed ices. Because the energy of solar UV photons decrease with altitude, most of these solid-state hydrocarbons will not be photochemically degraded and may contribute at the end to the organic layer that covers Titan's surface. As these materials would be probed by DraMS, the mass spectrometer on board the future Dragonfly mission, these analyses could serve as benchmarks for future molecule detection on Titan's surface.