Experimental Astrochemistry : from Ground-Based to Space-Borne Laboratories
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Experimental astrochemistry : from ground-based to space-borne laboratories Liège, 2-3 July 2014 Abstract book Development and optimization of an analytical system for the identification of volatile organic compounds coming from the heating of cometary ice analogs N. Abou-Mrad, F. Duvernay, T. Chiavassa, G. Danger Aix-Marseille University, France The chemical evolution of the organic matter in the universe can be studied through laboratory experiments in which the conditions of formation and evolution of this matter are experimentally simulated. This approach consists in reproducing a “primitive” ice analog such as a cometary one at low temperature (10-20 K) and low pressure (10-9 mbar). This ice analog is then subjected to various physico-chemical processes, such as heating or UV irradiation, mimicking what comets would experience in astrophysical environments. Studying the volatile organic compounds sublimating from these ice analogs may be of a great interest in the understanding of the formation of refractory organic residue representing the organic matter that could be present in interplanetary objects. On the other hand, these experiments will help for interpreting data coming from space missions such as Rosetta, and determining the compounds potentially present in protostellar environments (hot corinos). In this context, an original analytical system has been implemented to identify the volatiles coming from the heating of cometary ice analogs. The study is based on the online transfer of volatiles from their “source” to the instrument for their analysis. Briefly, the system is constituted of a cryogenic and ultra-vacuum chamber in which ice analogs are formed and heated. This chamber is connected via an interface for compound pre-concetration to a gas chromatography apparatus (GC) for compound separation coupled to an ion trap mass spectrometer (MS) for molecular structure identification. Herein we present the results of calibration and optimization of the system to ensure the best sensitivity and ruggedness. The optimal system is then tested with an ice analog allowing the unambiguous identification of the target product (aminoacetonitrile). Swift heavy ions, ices and astrophysics H. Rothard, P. Boduch CIMAP, Caen, France The main objective of this research program is to simulate the effects of heavy ion irradiation on astrophysical ices. Heavy ions (C, O, S, Fe, Ni) are present in the solar wind, in cosmic rays and in the magnetosphere of giant planets. Ices, found e.g. on comets and dust grains (dense clouds) in space are mainly formed by simple molecules (like H2O, CO, CO2, NH3 ...). In the laboratory, the icy samples are deposited at low temperature (typically 15K-150K) and are irradiated with swift heavy ions delivered by GANIL (Grand Accélérateur National d’Ions Lourds, Caen, France). In situ infrared absorption spectroscopy allows to observe the disappearance of molecules (fragmentation or sputtering), and the appearance of new molecular species as a function of the projectile fluence. Two examples will be presented: - High energy ion irradiation of CO and CO2 ices. In this domain (simulation of cosmic rays), the projectile deposits a large amount of energy on the electrons of the icy target. This leads to the destruction of the mother molecule, to sputtering and to the production of newly formed (daughter) molecules. - At low energy (solar wind and magnetospheres), the incoming ion is implanted in the icy mantle. The aim of this study is to know if the contribution of the implantation process can explaine the abundance of e.g. sulphuric acid, or SO2 and CO2 molecules on the Jovian moons. Simulating Titan atmospheric chemistry: from ground based experiments to the space platform AMINO-EXPOSE N. Carrasco LATMOS, University Paris 6 & Versailles, UMR 8190 CNRS, Verrières le Buisson, France On Titan, the dissociation of N2 and CH4 by solar UV radiation and Saturn’s magnetosphere electron bombardment induces a complex organic chemistry that results in the production of solid aerosols responsible for the orange haze surrounding Titan. These aerosols are nitrogen-rich as shown by the in-situ pyrolysis-MS analysis of the Huygens space-probe. Their chemical production mechanisms, initiated in the gaseous phase, remain mostly unknown and provide a great challenge in astrobiology. Experimental setups are being developed in order to reproduce and study in the lab such a complex atmospherical system. In LATMOS, we developed both a photochemical and a plasma reactor to study the effect of the energetic source on the chemistry. During experiments, solid organic particles, so called 'tholins' are produced in the reactive gas mixture. These tholins are analogues to photochemical aerosols of Titan's atmosphere. First space experiments were moreover successfully boarded on the International Space Station to simulate Titan's atmospheric photochemistry: the Titan-like cells of the AMINO-EXPOSE project. We will compare the complementary results provided recently by these both ground-based and space-platform experiments. Experimental simulation in the laboratory: Chemical evolution of the organic matter from interstellar or cometary ice analogs T. Chiavassa, N. Abou-Mrad, F. Duvernay, F. Borget, P. Theulé, G. Danger Aix-Marseille University, France The different approaches that are developed in the laboratory to study the chemical evolution of organic matter in stellar or interplanetary environments will be addressed. In the first approach, starting from interstellar or cometary ice analogs subjected to different energy processes (thermal, photochemical), we look for explaining the mechanism of formation of key molecules (RING project : Reactivity in INterstellar ice Grains) such as HMT, POM or amino acid precursors that may be detected in future space missions. In a second approach, we are interested in the detection of volatile molecules from ice analogs (VAHIIA project: Volatile Analysis from the Heating of Interstellar Ice Analogs) to simulate the effects of warming of the material when a young star forms or when a comet becomes active. This project aims to make an inventory of molecules found in hot corinos or in the gas phase comets through an online experimental device coupling our simulation chamber where ices are formed to a GC-MS instrument (see poster Abou Mrad et al. for the development and calibration of VAHIIA’s analytical system). In a third approach, we analyze the organic matter contained in refractory residues that can be considered as cometary analogs (RAHIIA Project: Residue analysis from the heating of Interstellar Ice Analogs) using ultra high resolution mass spectrometry (orbitrap). The results of these analyses show a great diversity of molecules in the residues and the possibility to determine their elementary composition that can be compared with meteorite composition. These residues are the basic material to start in a planetary environment, a prebiotic chemistry. UVolution, PROCESS, AMINO, PSS: compared photochemistry in low Earth orbit and in the laboratory for prebiotic organic compounds related to small bodies, Titan and Mars H. Cottin 1, K. Saiagh1, P. Coll1, N. Fray1, F. Raulin1, F. Stalport1, D. Khalaf1, M. Cloix1, P. Ehrenfreund2, A. Elsaesser2, N. Carrasco3, C. Szopa3, D. Chaput4, M. Bertrand5, F. Westall5, A. Mattioda6, R. Quinn6, A. Ricco6, O. Santos6, G. Baratta7, G. Strazzulla7, M.E. Palumbo7, A. Le Postollec8, M. Dobrijevic8, G. Coussot9, F. Vigier9, O. Vandenabeele-Trambouze9, S. Incerti10, T. Berger11 1 LISA, University Paris Est-Créteil & Paris Diderot, UMR 7583 CNRS, Créteil, France, 2 Leiden Institute of Chemistry, Leiden, Netherlands, 3 LATMOS, University Paris 6 & Versailles, UMR 8190 CNRS, Verrières le Buisson, France, 4 CNES, Centre spatial de Toulouse, Toulouse France, 5 CBM, CNRS, Orléans, France 6 NASA AMES Research Center , Moffet Field, CA, USA, 7 Osservatorio Astrofisico di Catania , Catania, Italy, 8 LAB, UMR 5804 CNRS,Floirac, France, 9 IBMM, Universités de Montpellier 1 & 2, Université de Montpellier 2, UMR 5247 CNRS, Montpellier, France, 10 CENBG, UMR 5797 CNRS, Gradignan, France, 11 German Aerospace Center, Institute of Aerospace Medicine, Cologne, Germany. Photochemistry plays a leading role in the chemical evolution of organic matter in the Solar System and in the interstellar medium, specifically in the VUV domain (vacuum ultra violet- < 200nm). For this reason, laboratory studies of the photolysis of organic compounds related to astrophysical environments are common and different kinds of UV sources are used, e.g. monochromatic (e.g. H2/He (122 nm), Xe (147 nm), CH4/He (193 nm) (Cottin et al., 2000) or simulating a wider range of UV (e.g. H2 (122 nm and 160 nm) or deuterium discharge lamp (190 - 400 nm) (Ten Kate et al., 2005), high pressure xenon lamps (190 - 400 nm) (Stalport et al., 2009). However, it is not possible to simulate accurately the whole range of wavelengths corresponding to the most energetic part of solar radiation below 200 nm (Cottin et al., 2008), therefore results obtained in the laboratory are extremely difficult to extrapolate to space environments (Guan et al., 2010). UV light reaching low Earth orbit (at the altitude of the International Space Station) is unfiltered. Thus, many samples can be exposed simultaneously in space experiments where photolysis is direct across the real solar UV spectrum and where the measurements can be easily extrapolated to various astrophysical environments. Moreover, the simulation of cosmic particles in