The Habitability of Hydrocarbon Words: Titan and Beyond

Titan is an ocean world, an icy world, and an organic world. We consider that Titans subsurface ocean and ductile ice are the most likely habitable environments on the moon. The ocean may be in contact with an organic-rich ice-rock core, potentially providing redox gradients, heavier elements, and organic building blocks critical for a habitable environment. Titans abundant surface organics could be delivered to the aqueous environment through processes such as impact cratering and potential convective cycles in the ice shell. Our work investigates the pathways for atmospheric organic products to be transported from the surface to the ocean/core and the potential for ocean/deep ice biosignatures and organisms to be transported to the shallow crust or surface for interrogation and discovery. Our overarching goal is to characterize the habitable environments on Titan and identify their potential biosignatures. We will present a summary of the work conducted by the team to date, which focuses on the following objectives: (i) Determine the pathways for organic materials to be transported (and modified) from the atmosphere to surface and eventually to the subsurface ocean (the most likely habitable environment). (ii) Determine whether the physical and chemical processes in the ocean create stable, habitable environments. (iii) Determine what biosignatures would be produced if the ocean is inhabited. (iv) Determine how biosignatures can be transported from the ocean to the surface and atmosphere and be recognizable at the surface and in the atmosphere.Figure: Titans potential geochemical pathways for organic materials to go from atmosphere to surface and ocean, and for extant chemical biosignatures to go up from the potentially habitable ocean to the surface and atmosphere. Acknowledgments: Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This work was funded by NASAs Astrobiology Institute grant NNN13D485T.