Titan's atmosphere from voyager infrared observations: I. The gas composition of Titan's equatorial region

摘要: The abundances of minor atmospheric constituents in Titan's equatorial region have been inferred from Voyager 1 infrared spectra. A temperature profile for the stratosphere was retrieved best fit 7.7-μm methane band which emission originates mainly pressure levels between 0.01 and 3 mbar (150 400 km). Assuming uniform vertical distributions all absorbers above their condensation levels, analysis three different selections yields stratospheric mole fractions following species: C2H2 (2.2+0.7−0.9 × 10−6), C2H4 (9.0+3−5 10−8), C2H6 (1.3+0.5−0.7 10−5), C3H4 (4.4+1.7−2.1 10−9), C3H8 (7.0+4−4 10−7), C4H2 (1.4+0.6−0.7 HCN (1.6+0.4−0.6 CO2 (1.4+0.3−0.5 10−8). Upper limits were obtained C2N2 (1.5 10−9) HC3N 10−9). An altitude-dependent tested against observations but no conclusive information as to distribution carbon dioxide could be extracted. formation lines components is found originate 20 (75 200 There evidence longitudinal variations composition. results are finally compared previous studies current photochemical models.