English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

During the accretion of Titan, impact heating may have been sufficient toallow the global melting of water ice and the release of volatile compounds,mainly constituted of CO2, CH4 and NH3. The duration and efficiency of exchangebetween the primitive massive atmosphere and the global impact-induced waterocean likely play a key role in the chemical evolution of the early Titan'satmosphere. To investigate the atmospheric composition of early Titan for awide range of global (atmosphere + ocean) composition in volatils, we firstdeveloped a gas-liquid equilibrium model of the NH3-CO2-H2O system, where thenon-ideal behavior of both gas and liquid phases, and the speciation ofvolatiles dissolved in the aqueous phase are taken into account. We show thatthe relative abundance of CO2 and NH3 determine the composition of Titan'satmosphere. For CO2/NH3 < 1, CO2 is massively dissolved in the ocean. On thecontrary, for CO2/NH3 > 1, CO2 is the main constituent of Titan's primitiveatmosphere while the NH3 atmospheric content is dramatically decreased. We theninvestigate the conditions for the formation of CH4-rich clathrates hydrates atTitan's surface that could be the main reservoir of methane for the present-dayatmosphere. In absence of reliable experimental data in the CH4-CO2-NH3-H2Osystem, the dissolution of methane in water is included using a simplifiedHenry's law approach. We find that if the concentration of CH4 in Titan'sbuilding block was higher than ~0.1 mol.kg-1 and CO2/NH3 < 3, a large fractionof methane may be stored in the primordial crust, which would form attemperature below ~10{\deg}C.

Role of the global water ocean on the evolution of Titan's primitive atmosphere