Near-infrared spectra of liquid/solid acetylene under Titan relevant conditions and implications for Cassini/VIMS detections

Autor: F. C. Wasiak, S. Singh, J. Ph. Combe, S. Le Mouélic, E. Le Menn, T. B. McCord, Vincent Chevrier, Thomas Cornet, L. A. Roe
Přispěvatelé: Canadian Explosives Research Laboratory, CANMET, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Arkansas Center for Space and Planetary Sciences, University of Arkansas [Fayetteville], Bear Fight Institute
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Icarus
Icarus, Elsevier, 2016, 270, pp.429-434. ⟨10.1016/j.icarus.2015.11.002⟩
ISSN: 0019-1035
1090-2643
DOI: 10.1016/j.icarus.2015.11.002⟩
Popis: Acetylene is thought to be abundant on Titan according to most photochemical models. While detected in the atmosphere, its likely presence at the surface still lacks physical evidence. It is thought that solid acetylene could be a major component of Titan’s lakes shorelines and dry lakebed, detected as the 5 μm-bright deposits with the Cassini/VIMS instrument. Acetylene could also be present under its liquid form as dissolved solids in Titan’s methane–ethane lakes, as emphasized by thermodynamics studies. This paper is devoted to the near-infrared spectroscopy study of acetylene under solid and liquid phases between 1 and 2.2 μm, synthesized in a Titan simulation chamber that is able to reproduce extreme temperature conditions. From experiments, we observed a ∼10% albedo increase between liquid acetylene at 193–188 K and solid acetylene at 93 K. Using the NIR spectroscopy technique we successfully calculated the reflectivity ratio of solid/liquid acetylene as 1.13. The second difference we observed between liquid and solid acetylene is a shift in the major absorption band detected at 1.54 μm, the shift of ∼0.01 μm occurring toward higher wavelength. In order to assess the detectability of acetylene on Titan using the Cassini/VIMS instrument, we adapted our spectra to the VIMS spectral resolution. The spectral band at 1.55 μm and a negative slope at 2.0 μm falls in the Cassini/VIMS atmospheric windows over several VIMS infrared spectels, thus Cassini/VIMS should be able to detect acetylene.
Databáze: OpenAIRE
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