Detection and mapping of hydrocarbon deposits on Titan

Journal of Geophysical Research - Planets
By: , and 



We report the identification of compounds on Titan's surface by spatially resolved imaging spectroscopy methods through Titan's atmosphere, and set upper limits to other organic compounds. We present evidence for surface deposits of solid benzene (C6H6), solid and/or liquid ethane (C2H6), or methane (CH4), and clouds of hydrogen cyanide (HCN) aerosols using diagnostic spectral features in data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS). Cyanoacetylene (2-propynenitrile, IUPAC nomenclature, HC3N) is indicated in spectra of some bright regions, but the spectral resolution of VIMS is insufficient to make a unique identification although it is a closer match to the feature previously attributed to CO2. We identify benzene, an aromatic hydrocarbon, in larger abundances than expected by some models. Acetylene (C2H2), expected to be more abundant on Titan according to some models than benzene, is not detected. Solid acetonitrile (CH3CN) or other nitriles might be candidates for matching other spectral features in some Titan spectra. An as yet unidentified absorption at 5.01-μm indicates that yet another compound exists on Titan's surface. We place upper limits for liquid methane and ethane in some locations on Titan and find local areas consistent with millimeter path lengths. Except for potential lakes in the southern and northern polar regions, most of Titan appears “dry.” Finally, we find there is little evidence for exposed water ice on the surface. Water ice, if present, must be covered with organic compounds to the depth probed by 1–5-μm photons: a few millimeters to centimeters.

Publication type Article
Publication Subtype Journal Article
Title Detection and mapping of hydrocarbon deposits on Titan
Series title Journal of Geophysical Research - Planets
DOI 10.1029/2009JE003369
Volume 115
Year Published 2010
Language English
Publisher American Geophysical Union
Contributing office(s) Astrogeology Science Center, Crustal Geophysics and Geochemistry Science Center, Denver Federal Center
Description E10005, 28 p.
Other Geospatial Titan
Google Analytic Metrics Metrics page
Additional publication details