Low-Temperature Alkaline pH Hydrolysis of Oxygen-Free Titan Tholins: Carbonates' Impact

Abstract

Titan, the largest moon of Saturn, is one of the key planetary objects in the field of exobiology. Its dense, nitrogen-rich atmosphere is the site of important organic chemistry. This paper focuses on the organic aerosols produced in Titan's atmosphere that play an important role in atmospheric and surface processes and in organic chemistry as it applies to exobiological interests. To produce reliable laboratory analogues of these aerosols, we developed, tested, and optimized a device for the synthesis of clean tholins. The potential chemical evolution of Titan aerosols at Titan's surface has been studied, in particular, the possible interaction between aerosols and putative ammonia-water cryomagma. Modeling of the formation of Saturn's atmosphere has permitted the characterization of a composition of salts in the subsurface ocean and cryolava. From this new and original chemical composition, a laboratory study of several hydrolyses of tholins was carried out. The results obtained show the formation of many organic compounds, among them, species identified only in the presence of salts. In addition, a list of potential precursors of these compounds was established, which could provide a database for research of the chemical composition of tholins and/or aerosols of Titan. Key Words: Titan tholins-Titan aerosols-Hydrolysis-Carbonates-Titan's surface. Astrobiology 17, 8-26.

Insights into Ceres's evolution from surface composition

“…A similar composition has also been inferred for Titan (Brassé et al. ). The recent detection of chlorides on Europa (Brown and Hand ) suggests that that Cl − may be the dominant salt anion over sulfate, and supports the idea that the presence of the latter on Europa's surface was supplied from Io (Hand and Carlson ).…”

“…As recent studies have pointed out the role of salts in promoting diverse organics production (e.g., Brassé et al. for Titan), Ceres's oceanic material exposed in many sites offers an opportunity to better comprehend environmental conditions and their impact on organic chemistry inside ocean worlds.…”

Experimental phase function and degree of linear polarization of cometary dust analogues

“…The tholins sample used in this work was synthesized using the PLASMA experimental setup described previously by Brassé et al (2017). It allows the production and sampling of tholins from N 2 -CH 4 electron irradiation in a glove box without contamination by the air of the laboratory.…”

Living at the Extremes: Extremophiles and the Limits of Life in a Planetary Context

“…Enceladus icy moon Plume jets 0~8.5 -9 High velocity jets > 0.5 90-99% H2O, ≤0.61-4.27% N2, 0.3-5.3% CO2, 0.1-1.68% CH4, 0.4-0.9% NH3, 0.4-39% H2, trace amounts of hydrocarbons; high mass organic cations, silicates, sodium, potassium, carbonates Gioia et al, 2007;Glein et al, 2015;Holm et al, 2015;Hsu et al, 2015;Postberg et al, 2009Postberg et al, , 2018Taubner et al, 2018;Waite et al, 2009;Zolotov et al, 2011 Baland et al, 2014;Brassé et al, 2017;Cordier et al, 2017;de Kok et al, 2007;Fulchignoni et al, 2005;Jennings et al, 2016;Mastrogiuseppe et al, 2014;McKay, 2016;Mitchell and Lora, 2016;Mitri et al, 2014;Norman, 2011;Sohl et al, 2014 Fanale and Salvail, 1989;Hayne and Aharonson, 2015;Hendrix et al, 2016;Küppers et al, 2014; Surface (-157--30) n 9.7-11.3 n nr <10 n Surface clays; (Mg, Ca)-carbonates; (Mg, NH4)-phyllosilicates; Fe-rich clays; salt deposits ; chloride salts; water-rock interactions; brucite and magnetite; sulfur species and graphitized carbon ; localized Na-carbonates (e.g.,Na2CO3), NH4Cl, NH4HCO3…”