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V. Vuitton, J.P. Ferris, B.N. Tran, P. Persans (Rensselaer Polytechnic Institute), J. Chera (GE Global Research Center)
A complex organic chemistry induced by charged particles and/or ultraviolet radiation produces a dense layer of haze in Titan’s stratosphere. Knowledge of the optical properties of the haze is necessary for modeling the dynamics and radiation transfer in Titan’s atmosphere. UV irradiations of gaseous mixtures representative of Titan’s atmospheric composition were used to produce Titan haze analogs. We report here the reflectance (R) and transmittance (T) of this polymer in the UV-vis NIR region (0.2 - 2.5 mm). From these measurements, the real (n) and imaginary (k) components of the refractive index in the 0.2 – 0.8 mm region were determined and compared with those measured for Titan's haze and for analogs formed in discharge reactions. At wavelengths longer than 0.8 mm, the very low absorbance of the polymer leads to a high uncertainty in the transmittance measurements. Then we used Photothermal Deflection Spectroscopy to measure the absorbance of the polymer in the “methane windows” at 0.83, 0.98 and 1.55 mm. The values of the complex refractive index (real and imaginary parts) were then retrieved. Analysis of the haze analogs by x-ray photoelectron spectroscopy revealed they had a much higher C/N ratio that analogs prepared in discharge reactions. The data obtained from this research will be useful to analyze the results obtained from the Huygens probe.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.