THE VARIABILITY OF HCN IN TITAN’S UPPER ATMOSPHERE AS IMPLIED BY THE CASSINI ION-NEUTRAL MASS SPECTROMETER MEASUREMENTS
AffiliationUniv Arizona, Lunar & Planetary Lab
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PublisherIOP PUBLISHING LTD
CitationTHE VARIABILITY OF HCN IN TITAN’S UPPER ATMOSPHERE AS IMPLIED BY THE CASSINI ION-NEUTRAL MASS SPECTROMETER MEASUREMENTS 2016, 826 (1):L5 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractHCN is an important constituent in Titan's upper atmosphere, serving as the main coolant in the local energy budget. In this study, we derive the HCN abundance at the altitude range of 960-1400 km, combining the Ion-Neutral Mass Spectrometer data acquired during a large number of Cassini flybys with Titan. Typically, the HCN abundance declines modestly with increasing altitude and flattens to a near constant level above 1200 km. The data reveal a tendency for dayside depletion of HCN, which is clearly visible below 1000 km but weakens with increasing altitude. Despite the absence of convincing anti-correlation between HCN volume mixing ratio and neutral temperature, we argue that the variability in HCN abundance makes an important contribution to the large temperature variability observed in Titan's upper atmosphere.
VersionFinal published version
SponsorsStrategic Priority Research Program of the Chinese Academy of Sciences [XDB09040400]; National Science Foundation of China (NSFC) [41374178, 41525015]; Science and Technology Development Fund of Macau SAR (FDCT) [039/2013/A2, 082/2015/A3]; French Space Agency (CNES); French National Program of Planetology (PNP); NASA Cassini Data Analysis and Participating Scientists (CDAPS) Program [NNX14AD51G]