The Fate of Simple Organics on Titan’s Surface: A Theoretical Perspective

By Keith Cowing
Status Report
January 8, 2024
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The Fate of Simple Organics on Titan’s Surface: A Theoretical Perspective
Ternary diagrams depicting the porosity levels required for selected ices to float on the ternary mixture. The light blue and pink diamond symbols indicate observed compositions of Titan’s northern and southern polar lakes, with diamond-shaped boxes showing the uncertainty (Poggiali et al., 2020). — astro-ph.EP

Atmospheric photochemistry on Titan continuously transforms methane and nitrogen gases into various organic compounds.

This study explores the fate of these molecules when they land on Titan’s surface. Our analytical exploration reveals that most simple organics found in Titan’s atmosphere, including all nitriles, triple-bonded hydrocarbons, and benzene, land as solids.

Only a few compounds are in the liquid phase, while only ethylene remains gaseous. For the simple organics that land as solids, we further examine their interactions with Titan’s lake liquids. Utilizing principles of buoyancy, we found that flotation can be achieved via porosity-induced (25-60% porosity) or capillary force-induced buoyancy for HCN ices on ethane-rich lakes.

Otherwise, these ices would sink and become lakebed sediments. By evaluating the timescale of flotation, our findings suggest that porosity-induced flotation of millimeter-sized and larger sediments is the only plausible mechanism for floating solids to explain the transient “magic islands” phenomena on Titan’s lakes.

Xinting Yu, Yue Yu, Julia Garver, Xi Zhang, Patricia McGuiggan

Comments: 11 pages, 4 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)
Cite as: arXiv:2401.02640 [astro-ph.EP] (or arXiv:2401.02640v1 [astro-ph.EP] for this version)
Journal reference: Geophysical Research Letters, 51, e2023GL105156
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Submission history
From: Xinting Yu
[v1] Fri, 5 Jan 2024 05:11:56 UTC (8,656 KB)
Astrobiology, Astrochemistry,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻