We performed laboratory experiments to study the photochemical evolution induced by long‐UV irradiation of benzene ices in Titan's atmosphere. The aim of this study was to investigate whether photo‐processed benzene ices could lead to the formatio...
We performed laboratory experiments to study the photochemical evolution induced by long‐UV irradiation of benzene ices in Titan's atmosphere. The aim of this study was to investigate whether photo‐processed benzene ices could lead to the formation of aerosols analogs to those observed in Titan's stratosphere. Prior to that, spectroscopic properties of amorphous and crystalline benzene ices were studied as a function of temperature, using infrared spectroscopy. UV photolysis experiments (λ > 230 nm) of benzene ices led to the formation of volatile photo‐products, among which fulvene is identified, and of a residue dominated by νCH IR features, demonstrating that pure aromatic‐based polymeric structures are not sufficient to explain the composition of Titan's stratospheric haze layer. However, we provide a characterization of long‐UV‐induced benzene‐containing aerosol analogs, which will contribute to Titan's surface organics layer. These data are of prime interest in the context of the future Dragonfly space mission.
Titan, often compared with the early Earth, is the only moon in the solar system to have a dense atmosphere, mainly composed of nitrogen and methane. In the upper part of the atmosphere (>1,000 km), UV photons, photoelectrons, energetic ions and magnetospheric electrons induce the dissociation and the ionization of nitrogen and methane. These reactions lead to the formation of complex organic molecules—including hydrocarbons such as benzene—and aerosols in the high atmosphere (an organic haze responsible for Titan's brownish color), which are subject to different UV radiation classes depending on the altitude. Therefore, during their sedimentation toward the surface, these organic photoproducts are expected to be modified. Once the tropopause is reached, molecules like benzene (C6H6) condense and could evolve under FUV radiations (λ > 200 nm) and contribute to aerosol formation.
Laboratory experiments demonstrate that the interaction between FUV photons and benzene ice leads to a solid‐state photochemical activity
The in situ monitoring by infrared spectroscopy of the benzene ice photolysis leads to identify the formation of one of benzene's isomer, fulvene
The photo‐produced residue presents some IR features similar to those of Titan's aerosols probed by Cassini/VIMS
Laboratory experiments demonstrate that the interaction between FUV photons and benzene ice leads to a solid‐state photochemical activity
The in situ monitoring by infrared spectroscopy of the benzene ice photolysis leads to identify the formation of one of benzene's isomer, fulvene
The photo‐produced residue presents some IR features similar to those of Titan's aerosols probed by Cassini/VIMS