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The Composition of Titan's Lower Atmosphere and Simple Surface Volatiles as Measured by the Cassini-Huygens Probe Gas Chromatograph Mass Spectrometer ExperimentThe Cassini-Huygens Probe Gas Chromatograph Mass Spectrometer (GCMS) determined the composition of the Titan atmosphere from ~140km altitude to the surface. After landing, it returned composition data of gases evaporated from the surface. Height profiles of molecular nitrogen (N2), methane (CH4) and molecular hydrogen (H2) were determined. Traces were detected on the surface of evaporating methane, ethane (C2H6), acetylene (C2H2), cyanogen (C2N2) and carbon dioxide (CO2). The methane data showed evidence that methane precipitation occurred recently. The methane mole fraction was (1.48+/-0.09) x 10(exp -2) in the lower stratosphere (139.8 km to 75.5 km) and (5.65+/-0.18) x 10(exp -2) near the surface (6.7 km to the surface). The molecular hydrogen mole fraction was (1.01+/-0.16) x 10(exp -3) in the atmosphere and (9.90+/-0.17) x 10(exp -4) on the surface. Isotope ratios were 167.7+/-0.6 for N-14/N-15 in molecular nitrogen, 91.1+/-1.4 for C-12/C-13 in methane and (1.35+/-0.30) x 10(exp -4) for D/H in molecular hydrogen. The mole fractions of Ar-36 and radiogenic Ar-40 are (2.1+/-0.8) x 10(exp -7) and (3.39 +/-0.12) x 10(exp -5) respectively. Ne-22 has been tentatively identified at a mole fraction of (2.8+/-2.1) x 10(exp -7) Krypton and xenon were below the detection threshold of 1 x 10(exp -8) mole fraction. Science data were not retrieved from the gas chromatograph subsystem as the abundance of the organic trace gases in the atmosphere and on the ground did not reach the detection threshold. Results previously published from the GCMS experiment are superseded by this publication.
Document ID
20110008599
Acquisition Source
Goddard Space Flight Center
Document Type
Other
Authors
Niemann, H. B.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Atreya, S. K.
(Michigan Univ. Ann Arbor, MI, United States)
Demick, J. E.
(Huntington Consulting Montgomery, AL, United States)
Gautier, D.
(Observatoire de Paris-Meudon France)
Haberman, J. A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Harpold, D. N.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kasprzak, W. T.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Lunine, J. I.
(Tor Vergata Univ. Rome, Italy)
Owen, T. C.
(Hawaii Univ. Honolulu, HI, United States)
Raulin, F.
(Centre National d'Etudes Spatiales Paris, France)
Date Acquired
August 25, 2013
Publication Date
January 1, 2010
Subject Category
Space Sciences (General)
Distribution Limits
Public
Copyright
Public Use Permitted.
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