Abstract：
:Saturn's largest moon, Titan, remains an enigma, explored only by remote sensing from Earth, and by the Voyager and Cassini spacecraft. The most puzzling aspects include the origin of the molecular nitrogen and methane in its atmosphere, and the mechanism(s) by which methane is maintained in the face of rapid destruction by photolysis. The Huygens probe, launched from the Cassini spacecraft, has made the first direct observations of the satellite's surface and lower atmosphere. Here we report direct atmospheric measurements from the Gas Chromatograph Mass Spectrometer (GCMS), including altitude profiles of the constituents, isotopic ratios and trace species (including organic compounds). The primary constituents were confirmed to be nitrogen and methane. Noble gases other than argon were not detected. The argon includes primordial 36Ar, and the radiogenic isotope 40Ar, providing an important constraint on the outgassing history of Titan. Trace organic species, including cyanogen and ethane, were found in surface measurements.
journal_name
Naturejournal_title
Natureauthors
Niemann HB,Atreya SK,Bauer SJ,Carignan GR,Demick JE,Frost RL,Gautier D,Haberman JA,Harpold DN,Hunten DM,Israel G,Lunine JI,Kasprzak WT,Owen TC,Paulkovich M,Raulin F,Raaen E,Way SHdoi
10.1038/nature04122keywords:
subject
Has Abstractpub_date
2005-12-08 00:00:00pages
779-84issue
7069eissn
0028-0836issn
1476-4687pii
nature04122journal_volume
438pub_type
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