Reflectance spectra of Titan tholin between 7000 and 10 cm-1. Interpretation of Cassini/CIRS observation of Saturn's satellite Phoebe - Université Pierre et Marie Curie Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2010

Reflectance spectra of Titan tholin between 7000 and 10 cm-1. Interpretation of Cassini/CIRS observation of Saturn's satellite Phoebe

Résumé

Context. Laboratory experiments provide a great support to astronomical studies in that they are the most suited technique to reproduce, model and interpret the observational data.
Aims: We investigate the spectroscopic properties of particulate and flat slab of tholin samples in a wide MIR and FIR spectral range at cryogenic temperature to contribute to the interpretation of the observation of Saturn satellite Phoebe obtained with the Cassini CIRS instrument.
Methods: Reflectance spectra of Titan tholin were obtained in the 7000-10 cm-1 spectral region by a Fourier transform spectrometer operating in vacuum. Several optical setups were used to cover this wide spectral range. Specular and diffuse reflectance spectra were obtained. A cryostat was interfaced to the spectrometer for reflectance measurements at low temperatures. It was cooled by a continuum flux of cryogenic fluid from about 300 to 72 K.
Results: It is shown that powder and slab tholin have a different reflectance that depends on geometrical factors and wavelength ranges. The emissivity of Phoebe is reproduced by flat slab tholin covered by a thin layer of water ice.
Conclusions: A considerable amount of compact smooth millimeter-size carbonaceous compounds are present on the Phoebe satellite covered with water ice and tholin regolith. This confirms a surface highly processed by small object impacts and a peculiar nature of Phoebe with respect to other Saturn satellites. It could be a primitive Kuiper belt object captured by Saturn that contains an high amount of HCN-like polymers active in prebiotic chemistry.
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hal-03786202 , version 1 (01-10-2022)

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John R. Brucato, Alessandra Migliorini, Maria Antonella Barucci, Jorge M. Carvano, Elisabetta Dotto, et al.. Reflectance spectra of Titan tholin between 7000 and 10 cm-1. Interpretation of Cassini/CIRS observation of Saturn's satellite Phoebe. Astronomy and Astrophysics - A&A, 2010, 516, pp.92. ⟨10.1051/0004-6361/200912054⟩. ⟨hal-03786202⟩
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