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 addition to UV photons requires additional tools (ion and electron guns) and increases the complexity of ground experiments. Therefore, space is a unique laboratory allowing the exposure of samples simultaneously to all space parameters as well as the irradiation of the samples under identical conditions. We will present a series of space exposure in low earth orbit (most of them outside of the International Space Station). The molecules selected for measuring their stability in space conditions are of different exobiological and general astrochemistry interest and include: nitrogenous bases (adenine, guanine…), amino acids (glycine, amino isobutyric acid…), and organic residues synthesized during laboratory irradiation of icy mixtures simulating interstellar and cometary ices. Carboxylic acids can also be selected for Mars-relevant’ research. Those compounds can be exposed either in pure form, or mixed with meteoritic powder or Mars soil analogue. Thanks to closed cells, gaseous mixtures simulating the atmosphere of Titan (N2 & CH4) can also be exposed. Biochips can also be tested versus exposure to cosmic rays. Their complex bio-organic structures could be used as detectors for specific organic compounds on Mars and are being developed for future exploration missions (Le Postollec et al., 2013). Their survival during space travel can then be tested. The LEO results will be compared with laboratory simulations to determine the differences between laboratory and space experiments and to attempt to improve laboratory sources. The hardware for such experiment will be presented and the improvements compared to previous LEO experiments will be discussed. The future of LEO facilities will also be discussed.

Interstellar and interplanetary solids in the laboratory

E. Dartois1,2, I. Alata1,2, C. Engrand3, R. Brunetto1,2, J. Duprat3, T. Pino4, E. Quirico5, L. Remusat6, N. Bardin3, G. Briani3, S. Mostefaoui6, G. Morinaud1,2, B. Crane1,2, N. Szwec1,2, L. Delauche3, F. Jamme7, Ch. Sandt7, P. Dumas7

1CNRS-INSU, Institut d'Astrophysique Spatiale, UMR 8617, 91405 Orsay, France 2Université Paris Sud, Institut d'Astrophysique Spatiale, UMR 8617, bât 121, 91405 Orsay, France 3Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Université Paris-Sud, UMR 8609-CNRS/IN2P3, F-91405 Orsay, France 4Institut des Sciences Moléculaires d’Orsay (ISMO), UMR 8214-CNRS Université Paris Sud, bât.210, F-91405 Orsay Cedex, France 5UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et dAstrophysique de Grenoble (IPAG), UMR 5274-CNRS INSU, F-38041 Grenoble, France 6Laboratoire de Minéralogie et Cosmochimie du Muséum (LMCM), UMR 7202–CNRS INSU, Muséum National d’Histoire Naturelle, 57 Rue Cuvier, 75231 Paris Cedex 05, France 7Synchrotron SOLEIL, L’orme des Merisiers, BP 48, Saint Aubin, F-91192 Gif sur Yvette, France

The interstellar medium is a physico-chemical laboratory where extremes conditions are encountered, and whose environmental parameters (e.g. density, reactant nature, radiations, temperature, time scales) define the composition of matter. Whereas cosmochemists can spectroscopically examine collected extraterrestrial material in the laboratory, astrochemists must rely on remote observations to monitor and analyze the physico- chemical composition of interstellar solids. The observations give essentially access to the molecular functionality of these solids, rarely elemental composition constraints and isotopic fractionation only in the gas phase. Astrochemists bring additional information from the study of analogs produced in the laboratory, placed in simulated space environments. In this presentation I will briefly touch some observations of the diffuse interstellar medium (DISM) and molecular clouds (MC), setting constraints on the composition of organic solids and large molecules. Massive stars: privileged sources of cosmic-rays for astrochemistry (Poster)

M. De Becker

Department of Astrophysics, Geophysics & Oceanography, University of Liège, Belgium

Massive stars can be considered as crucial engines for interstellar physics. They are indeed the main providers of UV radiation field, and constitute a substantial source of chemical enrichment. On their evolution time-scale (at most about 10 Myr), they typically stay close to their formation site, i.e. close to molecular clouds very rich in interstellar molecules. These stellar objects have also the property to be involved in particle acceleration processes leading to the production of high energy charged particles (cosmic-rays). After rejection in the interstellar medium, these particles will play a substantial role in processes such as those simulated in various facilities dedicated to experimental astrochemistry. This short contribution intends to put these particles, crucial for astrochemistry, in their adequate astrophysical context.

Organics Exposure in Orbit (OREOcube): a next-generation space exposure platform

A. Elsaesser et al.

Leiden University, The Netherlands

The OREOcube (ORganics Exposure in Orbit cube satellite) experiment on the International Space Station (ISS) investigates the effects of solar and cosmic radiation on organic thin films. By depositing organic samples onto inorganic substrates, structural changes and photo-modulated organic-inorganic interactions are examined to study the role that solid mineral surfaces play in the (photo-)chemical evolution, transport, and distribution of organics. The results of these experiments in low Earth orbit (LEO) allow extrapolation to different solar system and interstellar/interplanetary environments.

Controls on the recovery of mineral-associated biomolecules

P. Ehrenfreund et al.

Leiden University, The Netherlands

Direct detection of biomarkers on Mars or other planetary bodies is critically dependent upon the extractability and sensitivity of the detection methods. It is recognized that clay minerals, thought to represent important repositories of organic material, may impede life/ organic detection because of high surface retentivity of organics. We report on the adsorption characteristics of biomarkers on mineral surfaces and their recovery. These studies allow us to make informed decisions on developing and executing successful organic detection strategies and techniques on other planetary bodies, including Mars. Plasmon Polaritons to Study Molecules of Interest for Astrochemistry

K. Fleury-Frenette, J. Hastanin, C. Lenaerts

Centre Spatial de Liège, B29 Avenue du Pré-Aily, Liege Science Park, Angleur 4031, Belgium

The potential exploitation of plasmon-polariton resonance phenomena to investigate photosynthesis and photo-dissociation of molecules in space environments is addressed. Localized and delocalized surface plasmon resonances can be used to monitor minute changes in the effective refractive index of a liquid or an icy layer induced by chemical reactions within the layer. Alternatively, a more reaction-selective approach can be achieved through specific surface fonctionnalization of the plasmon-supporting material using the molecule of interest or a binding agent targeting this molecule or its byproducts. Transmission, total internal reflection and total internal reflection ellipsometry are considered as optical interrogation schemes. A plasmon resonance-based sensor architecture for a compact space-borne experiment is also presented.

CubeSat : A tool for Experimental Astrochemistry

N. Grand

LISA, University Paris Est-Créteil & Paris Diderot, UMR 7583 CNRS, Créteil, France

CubeSat is a wonderful tool for Student training as it is possible to complete a project from phase 0 to phase D in 3 or 4 years. It is also a very interesting tool to accelerate the process of readiness demonstrator for new technology in space. But it is also a very small satellite with limited power, volume and mass. One can ask if a so small satellite can be useful for science and in particular for experimental astrochemistry in space. In this presentation we will describe OGMS-SA a CubeSat developed at University of Paris-Est Créteil inside the ESEP consortium for the QB50 mission. And we will describe what is our long- term development plan to access chemistry science in earth-orbit with nano-satellites putting into light what will be necessary to develop in term of satellite platform and science instrument.

Photodesorption and photoprocessing of interstellar ice analogues using the Interstellar Astrochemistry Chamber

R. Martín-Doménech, G. M. Muñoz Caro

Centro de Astrobiología, Madrid, Spain

UV-photodesorption is a plausible non-thermal desorption process in dark clouds, which is required to explain the presence of molecules in the gas phase. Certain species detected in the gas are likely formed in dust grains. ISAC is an ultra-high-vacuum (UHV) set-up where an ice layer is deposited at 7 K. Samples are heated or UV-irradiated. The evolution of the ice is followed by in situ transmittance FTIR, while the volatile species are monitored by QMS. The temperature programmed desorption of ice mixtures with up to 5 components was studied. In addition, a vacuum-UV spectrometer monitors the UV flux and allows to perform ice spectroscopy in this spectral range. We will present our results on the UV-absorption cross sections of ices and their use for a proper study of ice photodesorption. We performed UV-photoprocessing of pure ices of astrophysical interest: H2O, NH3, CH4, CO, CO2, O2, N2, H2S, and CH3OH, studying the photodesorption of the starting molecules and their photoproducts. Thermal processing of astrophysical ice analogues using the Interstellar Astrochemistry Chamber (Poster)

R. Martín-Doménech, G. M. Muñoz Caro

Centro de Astrobiología, Madrid, Spain

Thermal processing of astrophysical ices takes place in circumstellar environments, around protostars (ice mantles on the surface of dust grains) or already formed stars (comets and other icy bodies). Temperature programmed desorption experiments of realistic astrophysical ice analogues composed of up to five molecular components (H2O, CO, CO2, CH3OH, and NH3) were performed with an ultra-high vacuum chamber (ISAC). Volatiles desorbing to the gas phase were monitored using a QMS, while changes in the ice structure and composition were studied by in situ transmittance FTIR. TPD curves of water ice containing CO, CO2, CH3OH, and NH3 present desorption peaks at temperatures near those observed in pure ice experiments. Desorption peaks of CH3OH, and NH3 at temperatures similar to the pure ices are observed when their abundance relative to water is above 3% in the ice matrix. Volcano desorption occurs after water ice crystallization, and co-desorption of the other four species with water is observed. We found that CO, CO2 and NH3 also present co-desorption peaks with CH3OH, the only species which was able to segregate to an extent enough to be detected by the FTIR spectrometer. This co-desorption cannot be reproduced in experiments with binary water-rich ice mixtures. These results reproduce the heating of circumstellar ices in hot cores, and will also aid to interpret the measurements that mass spectrometers on board the ESA-Rosetta cometary mission will perform on the coma of comet 67P/Churyumov-Gerasimenko.

Solid-phase chemistry driven by energetic processing

M.E. Palumbo

INAF – Osservatorio Astrofisico di Catania, Italy

Molecules in the solid phase have been detected in the line of sight of quiescent molecular clouds and star forming regions as icy mantles on dust grains. Although about 10 molecular species have been firmly identified in icy grain mantles, it is largely believed that many, also complex, species are present in the solid phase which are not detected due to the detection limits of infrared spectroscopy. It is generally accepted that some of the observed species (such as CO) freeze out from the gas phase while others (such as water and methanol) are formed on grains after surface reactions. Other species (such as CO2 and OCS), are not expected to freeze out from the gas phase and grain surface models do not account for their observed abundance. It has been suggested that these molecules, along with other more complex species, are formed after energetic processing (i.e. cosmic ion and UV irradiation) of icy grain mantles. All these species are released to the gas-phase after desorption of icy mantles. Here I will present some recent laboratory experiments which show the formation of (complex) molecular species after energetic processing (ion bombardment and UV photolysis) of simple ices. Icy targets have been processed by ion bombardment and UV photolysis both in separate experiments and for the first time simultaneously. When C-rich species are present in the initial ice, an organic refractory material is also formed. Photochemistry experiments in laboratory and Low Earth Orbit : studies of the stability of complex organics in a Martian environment

F. Stalport 1, T. Dequaire1, O. Poch2, P. Coll1, C. Szopa3, H. Cottin1

1LISA, Université Paris‐Est Créteil, Université Paris Diderot, CNRS, France, 2Center for Space and Habitability, University of Bern, Switzerland, 3LATMOS, UPMC Univ. Paris 6, Université Versailles St‐Quentin, CNRS, France

The search for organic carbon at the surface of Mars, as clues of past habitability or remnants of life, is a major science goal of Mars’ exploration. Understanding the chemical evolution of organic molecules under current Martian environmental conditions is essential to support the past, present and future analyses performed in situ. In this frame, the fate of organic molecules at the surface of Mars is of primary importance to determine how these molecules can evolve in such a harsh environment, and in this way, to determine their capability to survive and to be detected by surface rovers. One mean to characterize the way organic molecules can be processed at the surface of Mars is to submit such molecules to analogues conditions either reproduced in laboratory, or found in low Earth orbit. This methodology is used for years, especially concerning UV radiation, but the development of such approaches increased these last years in the favourable context of exploration of Mars. The goal of this presentation is to put the question raised by the environmental conditions of the Mars surface to the survival of organic molecules of interest for exo/astrobiology. It will particularly emphasize on the experimental and low Earth orbit approaches used to bring pieces of information on this fate.

CNES and astrochemistry in the laboratory and in space

M. Viso

CNES, France

(To be communicated)