The Search for n-Butane in Titan's Atmosphere

Abstract:

We have undertaken the search for n-butane (n-C₄H₁₀) signatures in the infrared (1100-1495 cm^-1) within the stratosphere of Titan (124-221 km above surface). We present here the results of this search thus far. The search was conducted using data obtained by the Cassini Composite Infrared Spectrometer instrument, via Focal Plane 4. These observations were modelled using the NEMESIS planetary atmosphere radiative transfer and retrieval tool. In addition to n-butane, our model incorporates nitrogen (N₂), methane (CH₄), ethane (C₂H₆), ethylene (C₂H₄), ethyne (C­₂H₂), propane (C₃H₈), and methyl cyanide (CH₃CN). Brand new pseudoline laboratory data from NASA Jet Propulsion Laboratory were used in the modeling of the n-butane spectrum. Constraining the abundance of butane in Titan’s atmosphere is important for the further development of numerical photochemical models, the use of which will improve our understanding of atmospheric processes in general on Titan and elsewhere. These results may also provide insight as to the rise of complex molecules and molecular structures in Titan's atmosphere. Our results may also contribute to our understanding of organic haze formation on Titan, and via this connection, may inform our understanding of exoplanetary atmospheres.