Planetary atmosphere observation analysis

Abstract:

This Letter reports the first detection of the three 13C isotopologues of HC3N on Titan, from Cassini Composite Infrared Spectrometer (CIRS) infrared spectra. The data are limb spectra taken at latitudes N54°-N69° in 2006 and 2007 when HC3N was enhanced in the north. Using a new line list for the vs bands of all isotopologues, we have modeled the isolated emission of H13CCCN at 658.7 cm-1 and both HC13CCN and HCC13CN at 663.0 cm-1, which are blended with the Q-branch of HC3N at 663.3 cm-1 at the resolution of CIRS (0.5 cm-1) and detectable as an increase in the intensity of the low-frequency wing. Using the resolved pair H13CCCN /HC3N we find 12C/ 13C = 79 ± 17, in line with other measurements on Titan from Cassini and Huygens. © 2008, The American Astronomical Society, All rights reserved.