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Start Over Author "Ludovic Vettier" Topic 0103 physical sciences
7 results on '"Ludovic Vettier"'

1. Interaction dust – plasma in Titan's ionosphere: An experimental simulation of aerosols erosion

Author

Olivier Guaitella, Thomas Gautier, Nathalie Ruscassier, Audrey Chatain, Nathalie Carrasco, Ludovic Vettier, IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-École polytechnique (X)-Sorbonne Universités-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie des Procédés et Matériaux (LGPM), CentraleSupélec-Université Paris-Saclay, and European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015)

Subjects
Atmosphere Evolution, 010504 meteorology & atmospheric sciences, Hydrogen, Analytical chemistry, chemistry.chemical_element, Infrared spectroscopy, FOS: Physical sciences, Organic chemistry, 01 natural sciences, Methane, Ion, Atmosphere, symbols.namesake, chemistry.chemical_compound, 0103 physical sciences, Capacitively coupled plasma, Spectroscopy, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Earth and Planetary Astrophysics (astro-ph.EP), Chemistry, Astronomy and Astrophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], symbols, Astrophysics - Instrumentation and Methods for Astrophysics, Titan (rocket family), Titan, Astrophysics - Earth and Planetary Astrophysics
Abstract

Organic aerosols accumulated in Titan's orange haze start forming in its ionosphere. This upper part of the atmosphere is highly reactive and complex ion chemistry takes place at altitudes from 1200 to 900 km. The ionosphere is a nitrogen plasma with a few percent of methane and hydrogen. Carbon from methane enables the formation of macromolecules with long organic chains, finally leading to the organic aerosols. On the other hand, we suspect that hydrogen and the protonated ions have a different erosive effect on the aerosols. Here we experimentally studied the effect of hydrogen and protonated species on organic aerosols. Analogues of Titan's aerosols were formed in a CCP RF plasma discharge in 95% N2 and 5% CH4. Thereafter, the aerosols were exposed to a DC plasma in 99% N2 and 1% H2. Samples were analysed by scanning electron microscopy and in situ infrared transmission spectroscopy. Two pellet techniques - KBr pressed pellets and thin metallic grids - were compared to confirm that modifications seen are not due to the material used to make the pellet. We observed that the spherical aerosols of ~500 nm in diameter were eroded under N2-H2 plasma exposure, with the formation of holes of ~10 nm at their surface. Aerosols were globally removed from the pellet by the plasma. IR spectra showed a faster disappearance of isonitriles and/or carbo-diimides compared to the global band of nitriles. The opposite effect was seen with beta-unsaturated nitriles and/or cyanamides. Double bonds as C=C and C=N were more affected than amines and C-H bonds. N-H and C-H absorption bands kept a similar ratio in intensity and their shape did not vary. Therefore, it seems that carbon and hydrogen play opposite roles in Titan's ionosphere: the carbon from methane lead to organic growth while hydrogen and protonated species erode the aerosols and react preferentially with unsaturated chemical functions., Comment: 30 pages, 16 figures

Published
2020
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2. Nitrogen-containing Anions and Tholin Growth in Titan’s Ionosphere: Implications for Cassini CAPS-ELS Observations

Author

Jérémy Bourgalais, Anne Wellbrock, David Dubois, R. T. Desai, Nathalie Carrasco, Andrew J. Coates, Ludovic Vettier, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Space Science and Astrobiology Division at Ames, NASA Ames Research Center (ARC), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Blackett Laboratory, Imperial College London, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Centre for Planetary Sciences [UCL/Birkbeck] (CPS), European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Dusty plasma, Astrochemistry, 010504 meteorology & atmospheric sciences, Analytical chemistry, FOS: Physical sciences, chemistry.chemical_element, methods: laboratory: molecular, 01 natural sciences, Ion, symbols.namesake, 0103 physical sciences, Molecule, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, planets and satellites: atmospheres, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], astrochemistry, planets and satellites: individual (Titan), Astronomy and Astrophysics, Tholin, Nitrogen, Charged particle, ISM: molecules, chemistry, 13. Climate action, Space and Planetary Science, symbols, Titan (rocket family), Astrophysics - Earth and Planetary Astrophysics
Abstract

The Cassini Plasma Spectrometer (CAPS) Electron Spectrometer (ELS) instrument onboard Cassini revealed an unexpected abundance of negative ions above 950 km in Titan's ionosphere. \textit{In situ} measurements indicated the presence of negatively charged particles with mass-over-charge ratios up to 13,800 \textit{u/q}. At present, only a handful of anions have been characterized by photochemical models, consisting mainly of C$_n$H$^-$ carbon chain and C$_{n-1}$N$^-$ cyano compounds ($n=2-6$); their formation occurring essentially through proton abstraction from their parent neutral molecules. However, numerous other species have yet to be detected and identified. Considering the efficient anion growth leading to compounds of thousands of \textit{u/q}, it is necessary to better characterize the first light species. Here, we present new negative ion measurements with masses up to 200 \textit{u/q} obtained in an \ce{N2}:\ce{CH4} dusty plasma discharge reproducing analogous conditions to Titan's ionosphere. We perform a comparison with high altitude CAPS-ELS measurements near the top of Titan's ionosphere from the T18 encounter. The main observed peaks are in agreement with the observations. However, a number of other species (\textit{e.g.} \ce{CNN-}, \ce{CHNN-}) previously not considered suggests an abundance of N-bearing compounds, containing two or three nitrogen atoms, consistent with certain adjacent doubly-bonded nitrogen atoms found in tholins. These results suggest that an N-rich incorporation into tholins may follow mechanisms including anion chemistry, further highlighting the important role of negative ions in Titan's aerosol growth., Comment: 8 pages, 2 figures, accepted for publication in the Astrophysical Journal Letters

Published
2019
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3. Organic chemistry in a CO2 rich early Earth atmosphere

Author

Cyril Szopa, Nathalie Carrasco, Ludovic Vettier, Benjamin Fleury, Maeva Millan, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), and European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015)

Subjects
prebiotic chemistry, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], chemistry.chemical_element, FOS: Physical sciences, chemistry, 01 natural sciences, Atmosphere, Lead (geology), Geochemistry and Petrology, Phase (matter), 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Molecule, Organic chemistry, Organic matter, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, chemistry.chemical_classification, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Earth, Early Earth, organic chemistry, Geophysics, 13. Climate action, Space and Planetary Science, atmospheres, Earth (chemistry), Carbon, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

International audience; The emergence of life on the Earth has required a prior organic chemistry leading to the formation of prebiotic molecules. The origin and the evolution of the organic matter on the early Earth is not yet firmly understood. Several hypothesis, possibly complementary, are considered. They can be divided in two categories: endogenous and exogenous sources. In this work we investigate the contribution of a specific endogenous source: the organic chemistry occurring in the ionosphere of the early Earth where the significant VUV contribution of the young Sun involved an efficient formation of reactive species. We address the issue whether this chemistry can lead to the formation of complex organic compounds with CO2 as only source of carbon in an early atmosphere made of N2, CO2 and H2, by mimicking experimentally this type of chemistry using a low pressure plasma reactor. By analyzing the gaseous phase composition, we strictly identified the formation of H2O, NH3, N2O and C2N2. The formation of a solid organic phase is also observed, confirming the possibility to trigger organic chemistry in the upper atmosphere of the early Earth. The identification of Nitrogen-bearing chemical functions in the solid highlights the possibility for an efficient ionospheric chemistry to provide prebiotic material on the early Earth.

Published
2017
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4. Organic Aerosols in the Presence of CO2 in the Early Earth and Exoplanets: UV–Vis Refractive Indices of Oxidized Tholins

Author

Ludovic Vettier, Nathalie Carrasco, Laurent Broch, Lisseth Gavilan, Benjamin Fleury, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes ( LCP-A2MC ), Université de Lorraine ( UL ), Jet Propulsion Laboratory ( JPL ), and NASA-California Institute of Technology ( CALTECH )

Subjects
010504 meteorology & atmospheric sciences, Band gap, Analytical chemistry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: spectroscopic, medicine.disease_cause, 01 natural sciences, Ultraviolet visible spectroscopy, Optics, Ellipsometry, 0103 physical sciences, medicine, Planets and satellites: atmospheres, Thin film, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, business.industry, Methods: laboratory, Astronomy and Astrophysics, Tholin, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Planets and satellites: fundamental parameters, Aerosol, 13. Climate action, Space and Planetary Science, business, Refractive index, Ultraviolet
Abstract

International audience; The goal of this experimental study is to investigate how the presence of atmospheric CO2 affects the optical properties of organic photochemical aerosols. To this end, we add CO2 to a N2:CH4 gas mixture used in a plasma typically used for Titan studies. We produce organic thin films (tholins) in plasmas where the CO2 / CH4 ratio is increased from 0 to 4. We measure these films via spectrometric ellipsometry in the ultraviolet, visible and near-infrared (270 nm to 2 µm). The ellipsometry parameters are fitted with a Tauc-Lorentz model used for optically transparent materials, to obtain the thickness of the thin film, its optical band gap, and the refractive indices. According to this optical mode, oxidized organic aerosols are transparent in the visible up to the near ultraviolet (k = 0 from 900-400 nm), while the fully reduced organic aerosol absorbs in the visible as well as in the near UV (k = 0 from 900-500 nm). As the CO2 /CH4 ratio is quadrupled, the position of the UV absorption resonance is shifted from ∼177 nm to 264 nm, and its strength is also quadrupled: oxidized tholins absorb more efficiently in the middle UV with respect to the far UV for reduced tholins. Our laboratory wavelength-tabulated refractive indices provide further constraints to atmospheric models of the early Earth and Earth-like exoplanets including photochemical hazes formed under increasingly oxidizing conditions.

Published
2017
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5. Aromatic Formation Promoted by Ion-Driven Radical Pathways in EUV Photochemical Experiments Simulating Titan’s Atmospheric Chemistry

Author

Jérôme Gaudin, Dominique Descamps, Nathalie Carrasco, Jérémy Bourgalais, Stéphane Petit, Antoine Comby, Ludovic Vettier, Valérie Blanchet, Yann Mairesse, Bernard Marty, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre d'Etudes Lasers Intenses et Applications (CELIA), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Bordeaux (UB), Programme d'investissements - Idex Bordeaux - LAPHIA LAPHIA ANR-10-IDEX-0302, European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015), European Project: 695618, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010304 chemical physics, Chemistry, 010402 general chemistry, Mass spectrometry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Atmosphere, symbols.namesake, 13. Climate action, [SDU]Sciences of the Universe [physics], Atmospheric chemistry, Extreme ultraviolet, 0103 physical sciences, Elementary reaction, symbols, Physical and Theoretical Chemistry, Atmosphere of Titan, Titan (rocket family), Electron ionization
Abstract

International audience; In the atmosphere of Titan, Saturn’s main satellite, molecular growth is initiated by 85.6 nm extreme ultraviolet (EUV) photons triggering a chemistry with charged and free-radical species. However, the respective contribution of these species to the complexification of matter is far from being known. This work presents a chemical analysis in order to contribute to a better understanding of aromatic formation pathways. A gas mixture of N2/CH4 (90/10%) within the closed SURFACAT reactor was irradiated at a relatively low pressure (0.1 mbar) and room temperature for 6 h by EUV photons (∼85.6 nm). The neutral molecules formed at the end of the irradiation were condensed in a cryogenic trap and analyzed by electron ionization mass spectrometry. An analysis of the dominant chemical pathways highlights the identification of benzene and toluene and underlies the importance of small ion and radical reactions. On the basis of the experimental results, a speculative mechanism based on sequential H-elimination/CH3-addition reactions is proposed for the growth of aromatics in Titan’s atmosphere. Elementary reactions to be studied are given to instill future updates of photochemical models of Titan’s atmosphere.

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6. In situ investigation of neutrals involved in the formation of Titan tholins

Author

Pascal Pernot, Ludovic Vettier, David Dubois, Nathalie Carrasco, Sarah Tigrine, Marie Petrucciani, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015)

Subjects
Dusty plasma, Materials science, 010504 meteorology & atmospheric sciences, Experimental techniques, FOS: Physical sciences, Mass spectrometry, 01 natural sciences, Methane, Astrobiology, Atmosphere, chemistry.chemical_compound, symbols.namesake, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Astronomy and Astrophysics, Tholin, Plasma, Saturn, chemistry, 13. Climate action, Space and Planetary Science, Atmospheric chemistry, Atmospheric Chemistry, symbols, Plasma discharge, Titan (rocket family), Titan, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Cassini Mission has greatly improved our understanding of the dynamics and chemical processes occurring in Titan's atmosphere. It has also provided us with more insight into the formation of the aerosols in the upper atmospheric layers. However, the chemical composition and mechanisms leading to their formation were out of reach for the instruments onboard Cassini. In this context, it is deemed necessary to apply and exploit laboratory simulations to better understand the chemical reactivity occurring in the gas phase of Titan-like conditions. In the present work, we report gas phase results obtained from a plasma discharge simulating the chemical processes in Titan's ionosphere. We use the PAMPRE cold dusty plasma experiment with an N2-CH4 gaseous mixture under controlled pressure and gas influx. An internal cryogenic trap has been developed to accumulate the gas products during their production and facilitate their detection. The cryogenic trap condenses the gas-phase precursors while they are forming, so that aerosols are no longer observed during the 2h plasma discharge. We focus mainly on neutral products NH3, HCN, C2H2 and C2H4. The latter are identified and quantified by in situ mass spectrometry and infrared spectroscopy. We present here results from this experiment with mixing ratios of 90-10% and 99-1% N2-CH4, covering the range of methane concentrations encountered in Titan's ionosphere. We also detect in situ heavy molecules (C7). In particular, we show the role of ethylene and other volatiles as key solid-phase precursors., Comment: 55 pages, 10 figures, 5 tables, Accepted for publication in Icarus

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7. Chemical composition of Pluto aerosol analogues

Author

Arnaud Buch, Nathalie Carrasco, Jérémy Bourgalais, Thomas Gautier, Laurène Flandinet, François-Régis Orthous-Daunay, Véronique Vuitton, Cédric Wolters, Lora Jovanovic, Ludovic Vettier, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire de Génie des Procédés et Matériaux (LGPM), CentraleSupélec-Université Paris-Saclay, European Project: 636829,H2020,ERC-2014-STG,PRIMCHEM(2015), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)

Subjects
Atmospheres, 010504 meteorology & atmospheric sciences, Analytical chemistry, chemistry.chemical_element, Organic chemistry, 01 natural sciences, 7. Clean energy, Atmosphere, chemistry.chemical_compound, 0103 physical sciences, Mixing ratio, Radiative transfer, 010303 astronomy & astrophysics, Chemical composition, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Pluto, Astronomy and Astrophysics, Nitrogen, Aerosol, Chemistry, chemistry, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Carbon monoxide
Abstract

Photochemical aerosols were observed in Pluto atmosphere during the New Horizons flyby on July 14th, 2015, as several thin haze layers extending at >350 km of altitude. This flyby has raised numerous questions on the aerosols formation processes and their impact on Pluto radiative transfer and climate. In order to gain a better understanding, we synthesized Pluto aerosol analogues in a room-temperature dusty plasma experiment and inferred their chemical composition from infrared spectroscopy, elemental composition analysis and very high-resolution mass spectrometry (ESI+/Orbitrap device). Three types of samples were synthesized at 0.9 ± 0.1 mbar, called P400, P600 and PCO-free. The samples P400 and P600 were produced from gas mixtures mimicking Pluto atmosphere at around 400 and 600 km of altitude, respectively, in order to determine if CH4 mixing ratio has an influence on the chemical composition of the aerosols. The sample PCO-free was produced from a gas mixture similar to the one forming the sample P400, but without carbon monoxide, in order to identify the impact of CO. Our study shows that the molecules constituting samples P400 and P600 are very rich in nitrogen atoms (up to 45% in mass of N elements) and, compared to the molecules constituting the PCO-free sample, a significant incorporation of oxygen atoms was detected. Moreover, our results on the variation of CH4 mixing ratio demonstrate that different ratios lead to different reactivity between N2, CH4 and CO. In particular, more nitrogen and oxygen atoms are detected in the bulk composition of the analogues P400. Due to the presence of nitrogenated and oxygenated molecules in the analogues of Pluto aerosols, we suggest that these aerosols will have an impact on Pluto radiative transfer, and thus on climate, that will differ from predictions based on the optical constants of Titan aerosol analogues.

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