THE APSIS EXPERIMENT: SIMULATING TITANS UPPER ATMOSPHERE AND ITS PHOTOCHEMISTRY IN THE VACUUM ULTRA-VIOLET VUVReportar como inadecuado




THE APSIS EXPERIMENT: SIMULATING TITANS UPPER ATMOSPHERE AND ITS PHOTOCHEMISTRY IN THE VACUUM ULTRA-VIOLET VUV - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

1 SSOLEIL - Synchrotron SOLEIL 2 IMPEC - LATMOS LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales 3 IUF - Institut Universitaire de France 4 LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales

Abstract : Titan, the largest moon of Saturn, has a dense atmosphere whose upper layers are mainly composed of methane CH4 and molecular nitrogen N2. The Cassini mission revealed that the interaction between those molecules and the solar VUV photons, as well as the electrons from Saturn’s magnetosphere, leads to a complex chemistry.Moreover, this naturally ionized environment contains heavy organic molecules like benzene C6H6 even at altitudes higher than 900 km.The presence of those molecules makes Titan a natural laboratory to witness and understand prebiotic-like chemistry but despite all the data collected, all the possible chemical processes in such a hydrocarbon-nitrogen-rich environment are not precisely understood. This is why Titan’s atmosphere simulation experiments are of high interest. We designed a gas reactor named APSIS for Atmospheric Photochemistry SImulated by Synchrotron which is to be coupled with a VUV photon source as N2 needs wavelengths shorter than 100 nm in order to be dissociated. The aim is to understand the key processes in the formation of those heavy compounds. We will present here our first experimental results obtained with APSIS coupled with this surfatron and then discuss them regarding the Cassini data, previous laboratory experiments and numerical models.





Autor: Sarah Tigrine - Nathalie Carrasco - Ludovic Vettier - Laurent Nahon -

Fuente: https://hal.archives-ouvertes.fr/



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