Liquid Chromatography Orbitrap Mass Spectrometry Study of Synthetic and Chondritic Organic Mixtures

International audienceLiquid chromatography Orbitrap mass spectrometry is used to compare extraterrestrial and synthetic organic matter. This analytical workflow brings information on the origin of the soluble organic matter present in carbonaceous chondrites

Cometary Materials Originating from Interstellar Ices: Clues from Laboratory Experiments

International audienceWe use laboratory experiments to derive information on the chemistry occurring during the evolution of astrophysical ices from dense molecular clouds to interplanetary objects. Through a new strategy that consists of coupling very high resolution mass spectrometry and infrared spectroscopy (FT-IR), we investigate the molecular content of the organic residues synthesized from different initial ice compositions. We also obtain information on the evolution of the soluble part of the residues after their over-irradiation. The results give insight into the role of water ice as a trapping and diluting agent during the chemical evolution. They also give information about the importance of the amount of ammonia in such ices, particularly regarding its competition with the carbon chemistry. All of these results allow us to build a first mapping of the evolution of soluble organic matter based on its chemical and physical history. Furthermore, our results suggest that interstellar ices should lead to organic materials enriched in heteroatoms that present similarities with cometary materials but strongly differ from meteoritic organic material, especially in their C/N ratios

Laboratory Simulation of Pluto's Atmosphere and Aerosols

International audienceWe will present laboratory investigation of Pluto's atmosphere and its aerosols formation to help understand the data provided by the New Horizons spacecraft

Laboratory experiments to unveil the molecular reactivity occurring during the processing of ices in the protosolar nebula

International audienceUsing laboratory experiments, we investigate the role of photo and thermal degradation in the possible complexification mechanisms of organic matter that may originate from interstellar ices prior to, or during the formation of the Solar System. We perform High Resolution Orbitrap Mass Spectrometry on organic residues formed from the photo- and thermochemical alterations of Interstellar Medium (ISM) dirty ice laboratory analogues. We probe, at the molecular level, the possible effects within the protosolar nebula on the composition and structure of these organic refractory materials obtained from an initial ice composition representative of astrophysical ices. We show that nitrogen incorporation, by competing with the carbon, has a strong influence on the final composition of the residue. NH3 rich ices lead to a group of unsaturated molecules in the final residue, while H2O rich ices lead to saturated ones. Finally, we observe and discuss the strong effect of UV irradiation on the decarboxylation on organic matter and discuss potential implications of this result for the protosolar nebula

Chemistry of Temperate Exoplanet Hazes from the Laboratory

International audienceLittle experimental work has been done to explore the properties of photochemical hazes formed in exoplanets, despite their role in atmospheric chemistry and their subsequent possible impact on observations. I will present results of the composition of haze particles produced from exoplanet laboratory studies in the JHU PHAZER laboratory. Post-haze production, we used very high resolution mass spectrometry to measure the chemical components of the solid particles. Many complex molecular species with general chemical formulae CwHxNyOz were detected. Molecular formulae of interest in the data include those with prebiotic implications, including amino acids, nucleobases, and simple sugars. Additionally, the experimental exoplanetary haze analogues exhibit diverse solubility characteristics, which may provide insight into the possibility of further chemical or physical alteration of photochemical hazes in exoplanet atmospheres. These laboratory particles can help us better understand chemical processes happening in exo-atmospheres and suggest a possible source of prebiotic chemistry on distant worlds

Characterization of laboratory analogs of interstellar/cometary organic residues using very high resolution mass spectrometry

WOS:000324035800012International audienceStudying the chemical composition of organic matter in astrophysical environments is an important means to improve our understanding of its origin and evolution. This organic matter evolves from molecular clouds to protoplanetary disks, and as a final destination, takes part in the formation of many objects of our solar system, such as primitive chondritic material, planetesimals and finally planets. In this contribution, we perform experimental simulations based on the VUV irradiation and warming-up of primitive interstellar ice analogs (CH3OH:NH3:H2O), and characterize, for the first time, the resulting refractory residue, using very high resolution mass spectrometry (VHRMS) with an LTQ-orbitrap-XL instrument. An electrospray source allows ionizing all the molecules having proton donor or acceptor chemical functions, while limiting as much as possible their damages. Thus, this method provides the analysis of the whole ionizable molecules making up the residue. The analysis of the spectra shows that these residues contain a large number of molecules formed of CHNO elements, including macromolecular entities beyond 4000 Da. The average elemental composition of the residue is of H/C = 1.5, N/C = 0.4, O/C = 0.4. These first results are tentatively compared to VHRMS analyses of the soluble organic matter (SOM) present in the Murchison's meteorite, a primitive chondrite of the CM class. The molecular richness observed can be considered as the "first step" of the complex abiotic organic matter in extraterrestrial media. This initial matter, that may be rather universal, could then evolve toward more processed materials in parent bodies, such as comets and asteroids, materials that are then observed and subsequently analyzed in meteorites found on Earth. In addition to providing some insight on the mixture complexity, VHRMS allows for the search of specific molecules. For instance, hexamethylenetetramine (HMT) and some of its derivatives are identified in these residues. With the possibility to characterize the whole residue as well as some specific molecules, we consider that VHRMS is a powerful analytical tool for the understanding of the chemical evolution of organic matter in astrophysical environments. (C) 2013 Elsevier Ltd. All rights reserved

Prevalence and nature of heating processes in CM and C2-ungrouped chondrites as revealed by insoluble organic matter

Chondrites are exhumed from their parent bodies by impacts, which at the same time can result in heating and mechanical modification (compaction, deformation, fracturing, etc.). However, whether impacts are responsible for the occurrence of heated C2s remains controversial since radiogenic and solar heating have also been invoked to explain them. Here we report a Raman and infrared study of the composition and structure of Insoluble Organic Matter (IOM) in a series of 39 CM and C2-ungrouped chondrites. These parameters are tracers of the extent and nature of thermal metamorphism a meteorite has experienced and reflect the degree to which the thermally driven and irreversible carbonization of IOM has proceeded. We propose a carbon-based classification of heated C2 chondrites that reveals a high occurrence frequency of thermally processed C2 chondrites (>36%). This classification is in agreement with the mineralogical classification scheme of Nakamura (2005). Strongly heated C2 chondrites (PCA 02012, PCA 91008, Y 96720) display an IOM structural evolution that is dissimilar to that of type 3 chondrites that experienced long duration radiogenic thermal metamorphism. These differences almost certainly reflect kinetic constraints on IOM modification during short duration heating events. QUE 93005 is a weakly heated chondrite that experienced a retrograde aqueous alteration. Its very aliphatic-rich IOM points to a parent body hydrogenation through interactions with water. The closed-system conditions required by this mechanism could be satisfied by a kinetic confinement during a very short duration impact. MET 01072, a heavily compacted and uni-axially deformed chondrite, did not experience post-accretional heating. In this case, the deformation features probably reflect a low-velocity impact. In contrast, the weakly metamorphosed chondrite EET 96029 experienced one or several low pressure impacts that triggered mild heating and partial dehydration without deformation features. The study of a series of lithologies from the Tagish Lake C2-ungrouped chondrite confirms the coexistence of various degrees of post-accretional alteration, the most altered lithologies having experienced a moderate degree of heating. Overall, the high prevalence of heating in C2 chondrites, the evidence of short-duration heating in the most heated C2s and the ability of low velocity collisions to trigger heating favor impacts (against solar heating), as the dominant heating mechanism. Finally, our set of data does not support the action of a low temperature oxidation process that would control the aliphatic abundance in unheated primitive C2s