Experimental simulation of Titan’s aerosols formation Thomas Gautier To cite this version: Thomas Gautier. Experimental simulation of Titan’s aerosols formation. Planétologie et astrophysique de la terre [astro-ph.EP]. Université de Versailles-Saint Quentin en Yvelines; Ruhr-Universität Bochum, 2013. Français. tel-00878846 HAL Id: tel-00878846 https://tel.archives-ouvertes.fr/tel-00878846 Submitted on 31 Oct 2013 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Thèse présentée pour l'obtention du titre de Docteur de l'Université de Versailles St Quentin en Yvelines. Spécialité: Astronomie Astrophysique. Dissertation zur Erlangung des Grades eines Doktors der Naturwissenschaften in der Fakultät für Physik und Astronomie der Ruhr Universität Bochum Experimental simulation of Titan’s aerosols formation by Thomas Gautier Soutenue le 20 Septembre 2013, devant un jury composé de: Pr. Philippe Bousquet Président Pr. Hervé Cottin Rapporteur Pr. Pascal Rannou Rapporteur Pr. Emmanuel Lellouch Examinateur Pr. Horst Fichtner Examinateur Pr. Jörg Winter Directeur Dr. Nathalie Carrasco Directrice Résumé ......................................................................................................................................... ChapterContents I : Titan - Observations and Experimental Simulations ......................................... 1 I.1 Titan ............................................................................................................................. 1 I.1.1 Past and present exploration ................................................................................. 1 I.1.2 Current knowledge on Titan's atmospheric aerosols ............................................ 4 I.2 Titan in a can: Laboratory analogs of Titan’s aerosols ............................................... 9 I.2.1 Gas Phase ........................................................................................................... 11 I.2.2 Tholins optical properties in the Infrared range ................................................. 12 I.3 Conclusion ................................................................................................................. 15 Chapter II Methods .............................................................................................................. 17 II.1 Experimental devices ................................................................................................. 17 II.1.1 The PAMPRE experiment: Synthesis of Titan's aerosols analogues ................. 17 II.1.2 Bochum setup ..................................................................................................... 23 II.1.3 Photochemical experiment: the APSIS setup ..................................................... 26 II.2 Ex-situ Analytical methods ....................................................................................... 29 II.2.1 Cryogenic trapping and Gas-Chromatography coupled to mass spectrometry: gas products identification. ............................................................................................... 29 II.2.2 Infrared analyses of tholins by ATR (performed at LATMOS) ......................... 30 II.2.3 Tholins infrared spectroscopy using Synchrotron radiation. ............................. 31 II.2.4 Ellipsometry: Determination of sample thickness. ............................................ 32 II.2.5 High resolution mass spectrometry for tholins chemical analysis ..................... 32 II.3 Conclusion ................................................................................................................. 34 Chapter III Gas phase reactivity leading to aerosols............................................................. 39 III.1 Introduction ............................................................................................................... 39 III.2 Volatile products in the PAMPRE experiment: in-situ look to the tholins nursery .. 39 III.2.1 Experimental protocol ........................................................................................ 40 III.2.2 The case of hydrogen: H and H2 ........................................................................ 43 III.2.3 Organic species production ................................................................................ 46 III.2.4 Implication for tholins formation processes: the case of ammonia and Methanimine ..................................................................................................................... 49 III.2.5 Conclusion .......................................................................................................... 53 III.3 Improving sensibility: Cold trap experiments ........................................................... 54 III.3.1 Experimental setup and protocol ........................................................................ 54 III.3.2 Results ................................................................................................................ 55 III.3.3 Discussion .......................................................................................................... 63 III.3.4 Conclusion .......................................................................................................... 71 III.4 Volatiles products in Bochum experiment: kinetics, products and quantification ... 73 III.4.1 Experimental parameters .................................................................................... 73 III.4.2 Providing Carbon for tholins formation: the consumption of methane.............. 74 III.4.3 Kinetics ............................................................................................................... 76 III.4.4 Identification by mass spectrometry .................................................................. 78 III.4.5 Identification by infrared spectroscopy .............................................................. 82 III.4.6 Absolute quantification of HCN and NH3 .......................................................... 86 III.5 Conclusion ................................................................................................................. 89 Chapter IV Tholins: What are they made of? How does it influence their properties? ........ 91 IV.1 Introduction ............................................................................................................... 91 IV.2 Insight into tholins chemical composition ................................................................. 92 IV.2.1 Time of Flight mass spectrometry: Global description of the sample ............... 92 IV.2.2 Orbitrap .............................................................................................................. 94 IV.2.3 Analysis of the residue by GC-MS .................................................................. 107 IV.2.4 Conclusion ........................................................................................................ 115 IV.3 Optical infrared properties ....................................................................................... 116 IV.3.1 Introduction ...................................................................................................... 116 IV.3.2 A first comparison of tholins produced in PAMPRE and Bochum: Attenuated Total Reflectance spectroscopy. ..................................................................................... 116 IV.3.3 Quantifying the tholins absorption and exploring their far-infrared absorbance properties. ........................................................................................................................ 120 IV.4 Conclusion ............................................................................................................... 133 Chapter V Effect of photochemistry: the APSIS experiment ............................................ 135 V.1 Introduction ............................................................................................................. 135 V.2 Analytical techniques and data treatment ................................................................ 136 V.2.1 In-situ Mass Spectrometry ............................................................................... 136 V.2.2 GC-MS ............................................................................................................. 138 V.3 Results ..................................................................................................................... 138 V.3.1 Methane consumption ...................................................................................... 138 V.3.2 Kinetics ............................................................................................................. 140 V.3.3 Products identification (GC-MS) ..................................................................... 142 V.3.4 Pressure influence on mass spectra .................................................................. 143 V.3.5 Products identification (MS) ...........................................................................