REMOVAL OF TITAN'S ATMOSPHERIC NOBLE GASES BY THEIR SEQUESTRATION IN SURFACE CLATHRATES
- Universite de Franche-Comte, Institut UTINAM, CNRS/INSU, UMR 6213, Observatoire des Sciences de l'Univers de Besancon (France)
- CRSR, Cornell University, Ithaca, NY 14853 (United States)
- Universite de Rennes 1, Institut de Physique de Rennes, CNRS, UMR 6251 (France)
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX 78228 (United States)
A striking feature of the atmosphere of Titan is that no heavy noble gases other than argon were detected by the Gas Chromatograph Mass Spectrometer aboard the Huygens probe during its descent to Titan's surface in 2005 January. Here we provide an explanation of the mysterious absence or rarity of these noble gases in Titan's atmosphere: the thermodynamic conditions prevailing at the surface-atmosphere interface of the satellite allow the formation of multiple guest clathrates that preferentially store some species, including all heavy noble gases, over others. The clean water ice needed for the formation of these clathrates could be delivered by successive episodes of cryovolcanic lavas that have been hypothesized to regularly cover the surface of Titan. The formation of clathrates in the porous lavas and their propensity for trapping Ar, Kr, and Xe would progressively remove these species from the atmosphere of Titan over the course of its history. In some circumstances, a global clathrate crust with an average thickness not exceeding a few meters could be sufficient on Titan for a complete removal of the heavy noble gases from the atmosphere.
- OSTI ID:
- 21565407
- Journal Information:
- Astrophysical Journal Letters, Vol. 740, Issue 1; Other Information: DOI: 10.1088/2041-8205/740/1/L9; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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