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1. Photocleavage of Aliphatic C–C Bonds in the Interstellar Medium

Author

Guillermo Tajuelo-Castilla, Jesús I. Mendieta-Moreno, Mario Accolla, Jesús M. Sobrado, Sofia Canola, Pavel Jelínek, Gary J. Ellis, José Ángel Martín-Gago, and Gonzalo Santoro

Subjects
Astrochemistry, Interstellar medium, Dense interstellar clouds, Laboratory astrophysics, Molecular physics, Interstellar dust processes, Astrophysics, QB460-466
Abstract

Ultraviolet (UV) processing in the interstellar medium (ISM) induces the dehydrogenation of hydrocarbons. Aliphatics, including alkanes, are present in different interstellar environments, being prevalently formed in evolved stars; thus, the dehydrogenation by UV photoprocessing of alkanes plays an important role in the chemistry of the ISM, leading to the formation of unsaturated hydrocarbons and eventually to aromatics, the latter ubiquitously detected in the ISM. Here, through combined experimental results and ab initio calculations, we show that UV absorption (mainly at the Ly α emission line of hydrogen at 121.6 nm) promotes an alkane to an excited Rydberg state from where it evolves toward fragmentation, inducing the formation of olefinic C=C bonds, which are necessary precursors of aromatic hydrocarbons. We show that the photochemistry of aliphatics in the ISM does not primarily produce direct hydrogen elimination but preferential C–C photocleavage. Our results provide an efficient synthetic route for the formation of unsaturated aliphatics, including propene and dienes, and suggest that aromatics could be formed in dark clouds by a bottom-up mechanism involving molecular fragments produced by UV photoprocessing of aliphatics.

Published
2024
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2. Metal-catalyst-free gas-phase synthesis of long-chain hydrocarbons

Author

Lidia Martínez, Pablo Merino, Gonzalo Santoro, José I. Martínez, Stergios Katsanoulis, Jesse Ault, Álvaro Mayoral, Luis Vázquez, Mario Accolla, Alexandre Dazzi, Jeremie Mathurin, Ferenc Borondics, Enrique Blázquez-Blázquez, Nitzan Shauloff, Rosa Lebrón-Aguilar, Jesús E. Quintanilla-López, Raz Jelinek, José Cernicharo, Howard A. Stone, Victor A. de la Peña O’Shea, Pedro L. de Andres, George Haller, Gary J. Ellis, and José A. Martín-Gago

Subjects
Science
Abstract

There is an urgent need of cleaner and energy-efficient technologies for future sustainable chemicals and fuels. Here the authors report the gas phase synthesis of long hydrocarbon chains from atomic carbon and molecular hydrogen precursors in an inert carrier gas, avoiding the use of metal catalysts.

Published
2021
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3. Prevalence of non-aromatic carbonaceous molecules in the inner regions of circumstellar envelopes

Author

Mario Accolla, Koen Lauwaet, José A. Martín-Gago, Jesús Manuel Sobrado, Roberto Otero, Gonzalo Santoro, Gary Ellis, Ramón J. Peláez, José Cernicharo, Isabel Tanarro, Hassan Sabbah, Alberto Martín-Jiménez, Christine Joblin, Marcelino Agúndez, Víctor J. Herrero, Lidia Martínez, Pablo Merino, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), and Comunidad de Madrid

Subjects
Photosphere, Materials science, Fullerene, 010504 meteorology & atmospheric sciences, Condensation, Nucleation, Astronomy and Astrophysics, Combustion, 01 natural sciences, Article, Astrobiology, Stars, 13. Climate action, Planet, 0103 physical sciences, Molecule, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

9 pags., 6 figs., Evolved stars are foundries of chemical complexity, gas and dust that provide the building blocks of planets and life, and dust nucleation first occurs in their photosphere. The circumstellar regions enveloping these stars, despite their importance, remain hidden to many observations, and dust formation processes are therefore still poorly understood. Laboratory astrophysics provides complementary routes to unveil these chemical processes, but most experiments rely on combustion or plasma decomposition of molecular precursors under physical conditions far removed from those in space. To reproduce and characterize the bottom-up dust formation process, we have built an ultra-high vacuum machine combining atomic gas aggregation with advanced in situ characterization techniques. We show that carbonaceous dust analogues that formed from low-pressure gas-phase condensation of carbon atoms in a hydrogen atmosphere, in a ratio of carbon to molecular hydrogen similar to that reported for evolved stars, lead to the formation of amorphous carbon nanograins and aliphatic carbon clusters. Aromatic species and fullerenes do not form effectively under these conditions, raising implications for a revision of the chemical mechanisms taking place in circumstellar envelopes., We thank the European Research Council for funding support under Synergy Grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). We also acknowledge partial support from the Spanish Research Agency (AEI) through grants MAT2017-85089-c2-1R, FIS2016-77578-R and FIS2016-77726-C3-1-P. Support from the FotoArt-CM Project (P2018/NMT-4367) through the Program of R&D activities between research groups in Technologies 2013, cofinanced by European Structural Funds, is also recognized.

Published
2019

4. Photolysis of Cometary Organic Dust Analogs on the EXPOSE-R2 Mission at the International Space Station

Author

Didier Chaput, Giovanni Strazzulla, G. A. Baratta, Maria Elisabetta Palumbo, Hervé Cottin, Mario Accolla, Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), ITA, and FRA

Subjects
Organic dust, Time Factors, Astrochemistry, Extraterrestrial Environment, 010504 meteorology & atmospheric sciences, Space (mathematics), Helium, 01 natural sciences, Astrobiology, 0103 physical sciences, International Space Station, Organic Chemicals, Spacecraft, 010303 astronomy & astrophysics, Research Articles, 0105 earth and related environmental sciences, Photolysis, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spectrum Analysis, Photodissociation, Dust, Meteoroids, Agricultural and Biological Sciences (miscellaneous), EXPOSE, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Environmental science
Abstract

International audience; We describe the results obtained on a set of organic samples that have been part of the experiment "Photochemistry on the Space Station (PSS)" on the EXPOSE-R2 mission conducted on the EXPOSE-R facility situated outside the International Space Station (ISS). The organic samples were prepared in the Catania laboratory by 200 keV He+ irradiation of N2:CH4:CO icy mixtures deposited at 17 K, on vacuum UV (VUV) transparent MgF2 windows. This organic material contains different chemical groups, including triple CN bonds, that are thought to be of interest for astrobiology. It is widely accepted that materials similar to that produced in the laboratory by ion irradiation of frozen ices could be present in some astrophysical environments such as comets. Once expelled from comets, these materials are exposed to solar radiation during their interplanetary journey. In the young Solar System, some of these processed materials could have reached early Earth and contributed to its chemical and prebiotic evolution. The samples were exposed for 16 months to the unshielded solar UV photons. It was found that, if an interplanetary dust particle (IDP) containing organic material (50% vol) is large enough (>20-30 μm), relevant chemical groups, such as those containing the CN triple bond, can survive for many years (>104 years) in the interplanetary medium.

Published
2019
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5. Silicon and Hydrogen Chemistry under Laboratory Conditions Mimicking the Atmosphere of Evolved Stars

Author

Lidia Martínez, Mario Accolla, Isabel Tanarro, Guillermo Tajuelo-Castilla, José A. Martín-Gago, José Cernicharo, Jesús Manuel Sobrado, Miguel Jiménez-Redondo, Christine Joblin, Víctor J. Herrero, Pablo Merino, Gonzalo Santoro, Luis Vázquez, Accolla, M. [0000-0002-9509-5967], Santoro, G. [0000-0003-4751-2209], Merino, P. [0000-0002-0267-4020], Martínez, L. [0000-0002-9370-2962], Tajuelo Castilla, G. [0000-0001-7877-2543], Vázquez, L. [0000-0001-6220-2810], Sobrado, J. M. [0000-0002-7359-0262], Agúndez, M. [0000-0003-3248-3564], Herrero, V. J. [0000-0002-7456-4832], Jiménez Redondo, M. [0000-0001-9221-8426], Tanarro, I. [0000-0002-1888-513X], Cernicharo, J. [0000-0002-3518-2524], Martín Gago, J. A. [0000-0003-2663-491X], European Commission (EC), Ministerio de Economía y Competitividad (MINECO), Comunidad de Madrid, and Agencia Estatal de Investigación (AEI)

Subjects
Astrochemistry, 010504 meteorology & atmospheric sciences, Silicon, Hydrogen, Silicate grains, chemistry.chemical_element, FOS: Physical sciences, 01 natural sciences, 7. Clean energy, Article, Astrobiology, Atmosphere, Interstellar Dust, Phase (matter), 0103 physical sciences, Interstellar Dust Processes, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Cosmic dust, Laboratory astrophysics, Chemistry, Condensation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Interestellar dust processes
Abstract

IOP Publishing [Society Publisher] Silicon is present in interstellar dust grains, meteorites and asteroids, and to date 13 silicon-bearing molecules have been detected in the gas phase toward late-type stars or molecular clouds, including silane and silane derivatives. In this work, we have experimentally studied the interaction between atomic silicon and hydrogen under physical conditions mimicking those in the atmosphere of evolved stars. We have found that the chemistry of Si, H, and H2 efficiently produces silane (SiH4), disilane (Si2H6) and amorphous hydrogenated silicon (a-Si:H) grains. Silane has been definitely detected toward the carbon-rich star IRC +10216, while disilane has not been detected in space yet. Thus, based on our results, we propose that gas-phase reactions of atomic Si with H and H2 are a plausible source of silane in C-rich asymptotic giant branch stars, although its contribution to the total SiH4 abundance may be low in comparison with the suggested formation route by catalytic reactions on the surface of dust grains. In addition, the produced a-Si:H dust analogs decompose into SiH4 and Si2H6 at temperatures above 500 K, suggesting an additional mechanism of formation of these species in envelopes around evolved stars. We have also found that the exposure of these dust analogs to water vapor leads to the incorporation of oxygen into Si–O–Si and Si–OH groups at the expense of SiH moieties, which implies that if this kind of grain is present in the interstellar medium, it will probably be processed into silicates through the interaction with water ices covering the surface of dust grains. We thank the European Research Council for funding support under Synergy grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). Also, we acknowledge partial support from the Spanish MINECO through grants MAT2017-85089-c2-1R, FIS2016-77726-C3-1-P, FIS2016-77578-R, AYA2016-75066-C2-1-P and RyC-2014-16277. Support from the FotoArt-CM Project (P2018/NMT 4367) through the Program of R&D activities between research groups in Technologies 2013, cofinanced by European Structural Funds, is also acknowledged. G.T.C. acknowledges funding from the Comunidad Autonoma de Madrid (PEJD-2018-PRE/IND-9029). Peerreview

Published
2021
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6. Metal-catalyst-free gas-phase synthesis of long-chain hydrocarbons

Author

Alexandre Dazzi, Mario Accolla, José A. Martín-Gago, Jesús Eduardo Quintanilla-López, Jesse T. Ault, Lidia Martínez, Stergios Katsanoulis, Gonzalo Santoro, Luis Vázquez, Jérémie Mathurin, Nitzan Shauloff, Pablo Merino, Alvaro Mayoral, Enrique Blázquez-Blázquez, Víctor A. de la Peña O’Shea, Raz Jelinek, Pedro L. de Andrés, José I. Martínez, George Haller, Ferenc Borondics, Gary Ellis, José Cernicharo, Rosa Lebrón-Aguilar, Howard A. Stone, European Research Council, Ministerio de Economía y Competitividad (España), Comunidad de Madrid, Ministerio de Ciencia e Innovación (España), Gobierno de Aragón, National Natural Science Foundation of China, ShanghaiTech University, German Research Foundation, Martínez, Lidia [0000-0002-9370-2962], Merino, Pablo [0000-0002-0267-4020], Santoro, Gonzalo [0000-0003-4751-2209], Martínez, José I. [0000-0002-2086-8603], Katsanoulis, Stergios [0000-0002-1186-5937], Mayoral, Álvaro [0000-0002-5229-2717], Vázquez, Luis [0000-0001-6220-2810], Accolla, Mario [0000-0002-9509-5967], Borondics, Ferenc [0000-0001-9975-4301], Blázquez-Blázquez, Enrique [0000-0003-2488-5635], Lebrón-Aguilar, Rosa [0000-0001-6103-6814], Quintanilla-López, Jesús Eduardo [0000-0003-1863-7408], Jelinek, Raz [0000-0002-0336-1384], Cernicharo, José [0000-0002-3518-2524], Stone, Howard A. [0000-0002-9670-0639], Peña O'Shea, Víctor A. de la [0000-0001-5762-4787], de Andrés Rodríguez, Pedro Luis [0000-0002-9012-2890], Haller, George [0000-0003-1260-877X], Ellis, Gary James [0000-0003-4851-6092], Martín-Gago, José A. [0000-0003-2663-491X], Martínez, Lidia, Merino, Pablo, Santoro, Gonzalo, Martínez, José I., Katsanoulis, Stergios, Mayoral, Álvaro, Vázquez, Luis, Accolla, Mario, Borondics, Ferenc, Blázquez-Blázquez, Enrique, Lebrón-Aguilar, Rosa, Quintanilla-López, Jesús Eduardo, Jelinek, Raz, Cernicharo, José, Stone, Howard A., Peña O'Shea, Víctor A. de la, de Andrés Rodríguez, Pedro Luis, Haller, George, Ellis, Gary James, Martín-Gago, José A., Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Max-Planck-Institut für Festkörperforschung, Max-Planck-Gesellschaft, Instituto de Física Fundamental [Madrid] (IFF), Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), ETH Zurich, School of Engineering (Brown Engineering), Brown University, ShanghaiTech University [Shanghai], University of Zaragoza - Universidad de Zaragoza [Zaragoza], Institut de Chimie Physique (ICP), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Instituto de Ciencia y Tecnologia de Polimeros (ICTP-CSIC), Ben-Gurion University of the Negev (BGU), Instituto de Química Física Rocasolano (IQFR), Department of Mechanical and Aerospace Engineering [Princeton] (MAE), Princeton University, Photoactivated Processes Unit IMDEA Energía, and European Project: 610256,EC:FP7:ERC,ERC-2013-SyG,NANOCOSMOS(2014)

Subjects
Work (thermodynamics), Materials science, carbon-based fuels, Catalyst synthesis, Science, Radical, General Physics and Astronomy, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, chemistry.chemical_compound, Lead (geology), alkane-based fuels, [CHIM]Chemical Sciences, metal catalysts, Methylene, Inert, Alkane, chemistry.chemical_classification, Multidisciplinary, Catalytic mechanisms, alkane-based chemicals, General Chemistry, 021001 nanoscience & nanotechnology, trap-andrelease mechanism, 3. Good health, 0104 chemical sciences, carbonaceous nanoparticles, chemistry, Chemical engineering, 13. Climate action, Nanoparticles, 0210 nano-technology, Carbon
Abstract

8 pags, 4 figs. -- The online version contains supplementary material available at https://doi.org/10.1038/s41467-021-26184-0, Development of sustainable processes for hydrocarbons synthesis is a fundamental challenge in chemistry since these are of unquestionable importance for the production of many essential synthetic chemicals, materials and carbon-based fuels. Current industrial processes rely on non-abundant metal catalysts, temperatures of hundreds of Celsius and pressures of tens of bars. We propose an alternative gas phase process under mild reaction conditions using only atomic carbon, molecular hydrogen and an inert carrier gas. We demonstrate that the presence of CH2 and H radicals leads to efficient C-C chain growth, producing micron-length fibres of unbranched alkanes with an average length distribution between C23-C33. Ab-initio calculations uncover a thermodynamically favourable methylene coupling process on the surface of carbonaceous nanoparticles, which is kinematically facilitated by a trap-and-release mechanism of the reactants and nanoparticles that is confirmed by a steady incompressible flow simulation. This work could lead to future alternative sustainable synthetic routes to critical alkane-based chemicals or fuels., We thank Jose Criado for the artwork schematics of the system, in figures 4 and S1; Funding: We thank the European Research Council for funding support under Synergy grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). Also, we acknowledge partial support from the Spanish MINECO through grants PID2020-113142RB-C21, PID2019106315RB-I00, and PID2019-106315RB-I00, EU ERC CoG HyMAP 648319, and from the regional government through project S2018-NMT-4367 (FotoArt-CM). AM acknowledges to the Spanish Ministry of Science (RYC2018-024561-I), to the Regional Government of Aragon (DGA E13_20R), to the National Natural Science Foundation of China (NFSC-21850410448, NSFC-21835002), and to the The Centre for Highresolution Electron Microscopy (ChEM), supported by SPST of ShanghaiTech University under contract No. EM02161943. S.K. and G.H. acknowledge funding from the Turbulent Superstructures Program of the German National Science Foundation (DFG)

Published
2021
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7. The Chemistry of Cosmic Dust Analogues from C, C

Author

Gonzalo, Santoro, Lidia, Martínez, Koen, Lauwaet, Mario, Accolla, Guillermo, Tajuelo-Castilla, Pablo, Merino, Jesús M, Sobrado, Ramón J, Peláez, Víctor J, Herrero, Isabel, Tanarro, Á Lvaro, Mayoral, Marcelino, Agúndez, Hassan, Sabbah, Christine, Joblin, José, Cernicharo, and José Ángel, Martín-Gago

Subjects
Article
Abstract

Interstellar carbonaceous dust is mainly formed in the innermost regions of circumstellar envelopes around carbon-rich asymptotic giant branch (AGB) stars. In these highly chemically stratified regions, atomic and diatomic carbon, along with acetylene are the most abundant species after H(2) and CO. In a previous study, we addressed the chemistry of carbon (C and C(2)) with H(2) showing that acetylene and aliphatic species form efficiently in the dust formation region of carbon-rich AGBs whereas aromatics do not. Still, acetylene is known to be a key ingredient in the formation of linear polyacetylenic chains, benzene and polycyclic aromatic hydrocarbons (PAHs), as shown by previous experiments. However, these experiments have not considered the chemistry of carbon (C and C(2)) with C(2)H(2). In this work, by employing a sufficient amount of acetylene, we investigate its gas-phase interaction with atomic and diatomic carbon. We show that the chemistry involved produces linear polyacetylenic chains, benzene and other PAHs, which are observed with high abundances in the early evolutionary phase of planetary nebulae. More importantly, we have found a non-negligible amount of pure and hydrogenated carbon clusters as well as aromatics with aliphatic substitutions, both being a direct consequence of the addition of atomic carbon. The incorporation of alkyl substituents into aromatics can be rationalized by a mechanism involving hydrogen abstraction followed by methyl addition. All the species detected in gas phase are incorporated into the nanometric sized dust analogues, which consist of a complex mixture of sp, sp(2) and sp(3) hydrocarbons with amorphous morphology.

Published
2020

8. INFRA-ICE: An ultra-high vacuum experimental station for laboratory astrochemistry

Author

José Cernicharo, Gary Ellis, Gonzalo Santoro, Lidia Martínez, Jon Azpeitia, Mario Accolla, José A. Martín-Gago, Jesús Manuel Sobrado, Guillermo Tajuelo-Castilla, Koen Lauwaet, European Commission, Ministerio de Economía y Competitividad (España), Comunidad de Madrid, Castilla, G. [0000-0001-7877-2543], Cernicharo, J. [0000-0002-3518-2524], Martín Gago, J. A. [0000-0003-2663-491X], Santoro, G. [0000-0003-4751-2209], Martínez Orellana, L. [0000-0002-9370-2962], Sobrado, J. M. [0000-0002-7359-0262], Ellis, G. [0000-0003-4851-6092], European Commission (EC), Spanish Research Agency (AEI), European Research Council (ERC), FotoArt-CM Project, and Comunidad Autónoma de Madrid

Subjects
010302 applied physics, Physics, Physics - Instrumentation and Detectors, Astrochemistry, Molecular cloud, Comet, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 7. Clean energy, Article, 010305 fluids & plasmas, Astrobiology, Interstellar medium, Chemical species, Stars, 0103 physical sciences, Asymptotic giant branch, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Instrumentation, Astrophysics::Galaxy Astrophysics, Cosmic dust
Abstract

12 pags., 8 figs., 1 tab., Laboratory astrochemistry aims at simulating, in the laboratory, some of the chemical and physical processes that operate in different regions of the universe. Amongst the diverse astrochemical problems that can be addressed in the laboratory, the evolution of cosmic dust grains in different regions of the interstellar medium (ISM) and its role in the formation of new chemical species through catalytic processes present significant interest. In particular, the dark clouds of the ISM dust grains are coated by icy mantles and it is thought that the ice–dust interaction plays a crucial role in the development of the chemical complexity observed in space. Here, we present a new ultra-high vacuum experimental station devoted to simulating the complex conditions of the coldest regions of the ISM. The INFRA-ICE machine can be operated as a standing alone setup or incorporated in a larger experimental station called Stardust, which is dedicated to simulate the formation of cosmic dust in evolved stars. As such, INFRA-ICE expands the capabilities of Stardust allowing the simulation of the complete journey of cosmic dust in space, from its formation in asymptotic giant branch stars to its processing and interaction with icy mantles in molecular clouds. To demonstrate some of the capabilities of INFRA-ICE, we present selected results on the ultraviolet photochemistry of undecane (C11H24) at 14 K. Aliphatics are part of the carbonaceous cosmic dust, and recently, aliphatics and short n-alkanes have been detected in situ in the comet 67P/Churyumov–Gerasimenko., We thank the European Research Council for funding support under Synergy Grant No. ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). In addition, partial support from the Spanish Research Agency (AEI) through Grant Nos. MAT2017-85089- c2-1R and FIS2016-77578-R is acknowledged. Support from the FotoArt-CM Project (No. P2018/NMT 4367) through the Program of R&D activities between research groups in Technologies 2013, co-financed by European Structural Funds, is also acknowledged. G.T.-C. acknowledges funding from the Comunidad Autónoma de Madrid (Grant No. PEJD-2018-PRE/IND-9029).

Published
2020

9. Comet 67P/Churyumov–Gerasimenko preserved the pebbles that formed planetesimals

Author

M. Ferrari, Stavro Ivanovski, Mario Accolla, Roberto Sordini, F. J. M. Rietmeijer, Marco Fulle, J. J. López-Moreno, Luigi Colangeli, E. Mazzotta Epifani, J. E. Rodriguez, Pasquale Palumbo, V. V. Zakharov, Jose Luis Ortiz, R. Morales, Alessandra Rotundi, P. Weissman, Simon F. Green, Ernesto Palomba, V. Della Corte, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), British Geological Survey [Edinburgh], British Geological Survey (BGS), Planetary Science Institute [Tucson] (PSI), INAF - Osservatorio Astrofisico di Catania (OACT), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), INAF - Osservatorio Astronomico di Capodimonte (OAC), Instituto de Astrofsica de Andalucia, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Waves and Solitons LLC, 918 W. Windsong Dr., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), and Agenzia Spaziale Italiana

Subjects
Planetesimal, 010504 meteorology & atmospheric sciences, Comets: general, Comets: individual: 67P/Churyumov, Gerasimenko, Space vehicles, Astronomy and Astrophysics, Space and Planetary Science, Astrophysics, 01 natural sciences, individual: 67P/Churyumov [Comets], 0103 physical sciences, 10. No inequality, Porosity, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], comets: general, general [Comets], comets: individual: 67P/Churyumov-Gerasimenko, Mass ratio, Bulk density, Amorphous solid, Volume filling, [SDU]Sciences of the Universe [physics], 13. Climate action, space vehicles, Formation and evolution of the Solar System
Abstract

Solar system formation models predict that the building blocks of planetesimals were mm- to cm-sized pebbles, aggregates of ices and non-volatile materials, consistent with the compact particles ejected by comet 67P/Churyumov-Gerasimenko (67P hereafter) and detected by GIADA (Grain Impact Analyzer and Dust Accumulator) on-board the Rosetta spacecraft. Planetesimals were formed by the gentle gravitational accretion of pebbles, so that they have an internal macroporosity of 40 per cent. We measure the average dust bulk density ¿D = 795+840 -65 kg m-3 that, coupled to the nucleus bulk density, provides the average dust-toices mass ratio ¿ = 8.5. We find that the measured densities of the 67P pebbles are consistent with a mixture of (15 ± 6) per cent of ices, (5 ± 2) per cent of Fe-sulphides, (28 ± 5) per cent of silicates, and (52 ± 12) per cent of hydrocarbons, in average volume abundances. This composition matches both the solar and CI-chondritic chemical abundances, thus showing that GIADA has sampled the typical non-volatile composition of the pebbles that formed all planetesimals. The GIADA data do not constrain the abundance of amorphous silicates versus crystalline Mg, Fe-olivines and pyroxenes. We find that the pebbles have a microporosity of (52 ± 8) per cent (internal volume filling factor ¿P = 0.48 ± 0.08), implying an average porosity for the 67P nucleus of (71 ± 8) per cent, lower than previously estimated. © 2016 The Authors., This research was supported by the Italian Space Agency (ASI) within the INAF-ASI agreements I/032/05/0 and I/024/12/0.

Published
2016
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10. GIADA – Grain Impact Analyzer and Dust Accumulator – Onboard Rosetta spacecraft: Extended calibrations

Author

E. Mazzotta-Epifani, F. J. M. Rietmeijer, M. Cosi, J. J. López-Moreno, M. Ferrari, Mario Accolla, Stavro Ivanovski, J. E. Rodriguez, R. Morales, Pasquale Palumbo, Alessandra Rotundi, V. Della Corte, Marco Fulle, Luigi Colangeli, Roberto Sordini, ITA, USA, and ESP

Subjects
Physics, Spectrum analyzer, 010504 meteorology & atmospheric sciences, Spacecraft, Accumulator (structured product), Calibration curve, business.industry, Comet, Dust particles, Aerospace Engineering, Rosetta Esa Mission, GIADA, 01 natural sciences, Calibration, Coma dust environment, Dust dynamical properties, 0103 physical sciences, business, 010303 astronomy & astrophysics, Data calibration, 0105 earth and related environmental sciences, Remote sensing
Abstract

Despite a long tradition of dust instruments flown on-board space mission, the largest number of these can be considered unique as they used different detection techniques. GIADA (Grain Impact Analyzer and Dust Accumulator), is one of the dust instruments on-board the Rosetta spacecraft and is devoted to measure the dust dynamical parameters in the coma of comet 67P/Churyumov–Gerasimenko. It couples two different techniques to measure the mass and speed of individual dust particles. We report here the results of an extended calibration activity carried-out, during the hibernation phase of the Rosetta mission, on the GIADA Proto Flight Model (PFM) operative in a clean room in our laboratory. The main aims of an additional calibration campaign are: • to verify the algorithms and procedures for data calibration developed before Rosetta launch; • to improve the comprehension of GIADA response after the increased knowledge on cometary dust, e.g. the composition of dust particles after Stardust mission. These calibration improvements implied a final step, which consisted in defining transfer functions to correlate the new calibration curves obtained for the GIADA PFM to those to be used for GIADA onboard the Rosetta spacecraft. The extended calibration activity allowed us to analyze GIADA data acquired in the 67P/C–G coma permitting to infer additional information on cometary dust particles, e.g. density and tensile strength.

Published
2016
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11. The Chemistry of Cosmic Dust Analogs from C, C2, and C2H2 in C-rich Circumstellar Envelopes

Author

Lidia Martínez, Christine Joblin, Mario Accolla, Gonzalo Santoro, José A. Martín-Gago, Pablo Merino, Jesús Manuel Sobrado, Hassan Sabbah, Guillermo Tajuelo-Castilla, Alvaro Mayoral, Koen Lauwaet, Ramón J. Peláez, José Cernicharo, Marcelino Agúndez, Víctor J. Herrero, Isabel Tanarro, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), IMDEA Nanociencia (IMDEA), Instituto de Física Fundamental [Madrid] (IFF), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Instituto de Estructura de la Materia (IEM), ShanghaiTech University [Shanghai], Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Santorio, G. [0000-0003-4751-2209], Accolla, M. [0000-0002-9509-5967], Agúndez, M. [0000-0003-3248-3564], Sabbah, H. [0000-0001-5722-4388], Joblin, C. [0000-0003-1561-6118], Cernicharo, J. [0000-0002-3518-2524], Martín Gago, J. M. [0000-0003-2663-491X], European Commission (EC), Ministerio de Ciencia e Innovación (MICINN), Comunidad de Madrid, Ministerio de Economía y Competitividad (MINECO), European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
stars, 010504 meteorology & atmospheric sciences, Asymptotic giant branch, FOS: Physical sciences, chemistry.chemical_element, Photochemistry, 01 natural sciences, Plasma physics, lines and bands -methods, chemistry.chemical_compound, 0103 physical sciences, Diatomic carbon, Benzene, Post-asymptotic giant branch, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Cosmic dust, Laboratory astrophysics, Protoplanetary nebulae, extinction -ISM, Astronomy and Astrophysics, Circumstellar matter, solid state, [CHIM.MATE]Chemical Sciences/Material chemistry, Astrophysics - Astrophysics of Galaxies, 3. Good health, Circumstellar dust, Astrophysics - Solar and Stellar Astrophysics, chemistry, Acetylene, AGB and post-AGB -circumstellar matter -dust, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), molecular -methods, Atomic carbon, Molecular physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], laboratory, Carbon
Abstract

13 pags., 12 figs., 2 tabs., Interstellar carbonaceous dust is mainly formed in the innermost regions of circumstellar envelopes around carbon-rich asymptotic giant branch stars (AGBs). In these highly chemically stratified regions, atomic and diatomic carbon, along with acetylene, are the most abundant species after H and CO. In a previous study, we addressed the chemistry of carbon (C and C) with H showing that acetylene and aliphatic species form efficiently in the dust formation region of carbon-rich AGBs whereas aromatics do not. Still, acetylene is known to be a key ingredient in the formation of linear polyacetylenic chains, benzene, and polycyclic aromatic hydrocarbons (PAHs), as shown by previous experiments. However, these experiments have not considered the chemistry of carbon (C and C) with CH. In this work, by employing a sufficient amount of acetylene, we investigate its gas-phase interaction with atomic and diatomic carbon. We show that the chemistry involved produces linear polyacetylenic chains, benzene, and other PAHs, which are observed with high abundances in the early evolutionary phase of planetary nebulae. More importantly, we have found a nonnegligible amount of pure and hydrogenated carbon clusters as well as aromatics with aliphatic substitutions, both being a direct consequence of the addition of atomic carbon. The incorporation of alkyl substituents into aromatics can be rationalized by a mechanism involving hydrogen abstraction followed by methyl addition. All the species detected in the gas phase are incorporated into nanometric-sized dust analogs, which consist of a complex mixture of sp, sp, and sp hydrocarbons with amorphous morphology., We thank the European Research Council for funding support under Synergy grant ERC-2013-SyG, G.A. 610256 (NANOCOSMOS). Also, partial support from the Spanish Research Agency (AEI) through grants MAT2017-85089-c2- 1R, FIS2016-77578-R, FIS2016-77726-C3-1-P, AYA2016- 75066-C2-1-P, and RyC-2014-16277 is acknowledged. Support from the FotoArt-CM Project (P2018/NMT 4367) through the Program of R&D activities between research groups in Technologies 2013, co-financed by European Structural Funds, is also acknowledged. G.TC. acknowledges funding from the Comunidad Autónoma de Madrid (PEJD-2018-PRE/ IND-9029)

Published
2020
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12. Combined IR and XPS characterization of organic refractory residues obtained by ion irradiation of simple icy mixtures

Author

Giovanni Strazzulla, Gleb Fedoseev, Maria Elisabetta Palumbo, G. A. Baratta, Giovanna Pellegrino, Guglielmo G. Condorelli, Mario Accolla, C. Scirè, and ITA

Subjects
Physics, SIMPLE (dark matter experiment), Astrochemistry, Methods: Laboratory: Solid state, Inorganic chemistry, Astronomy and Astrophysics, 02 engineering and technology, Astrophysics, Astrobiology, Space and Planetary Science, 021001 nanoscience & nanotechnology, 01 natural sciences, Characterization (materials science), Ion, X-ray photoelectron spectroscopy, 0103 physical sciences, Irradiation, 0210 nano-technology, 010303 astronomy & astrophysics, Refractory (planetary science)
Abstract

Context. Multi-year laboratory experiments have demonstrated that frozen icy mixtures containing simple organic and inorganic molecules (such as H2O, N2, CH4, CO, CO2, C2H6, etc.), if exposed to a flux of energetic ions or UV photons, give rise to new more complex molecules at low temperatures (10–50 K). A fraction of the new synthesized molecules is volatile while the remaining fraction is refractory and therefore it is preserved after the warm-up of the substrate to room temperature. Moreover, a part of the refractory material is formed during the annealing to room temperature, when molecules and radicals into the processed ice become mobile and react to form non-volatile molecules. By means of similar mechanisms, complex organic materials may be formed on the icy surfaces of some objects in the outer solar system, such as trans-Neptunian objects, comets and some satellites of the giant planets: in fact the interaction with solar wind and solar flares ions, solar photons and galactic cosmic rays could produce more refractory materials, analogous to those produced in the laboratory. In some cases, the materials thus synthesized may contain functional groups considered relevant to the pre-biotic chemistry in the hypothesis that interplanetary dust particles, comets and meteoroids contributed to seed the early Earth with the building blocks of life. Aims. The aim of this work is to investigate the chemical similarities and differences between some organic residues left over after ion bombardment (200 keV H+) of different ice mixtures followed by subsequent warm up under vacuum to room temperature. Methods. Seven organic residues have been prepared in our laboratory following a procedure involving the proton irradiation of seven different icy mixtures and their warm-up to room temperature. All the organic samples were characterized by FTIR spectroscopy with measurements performed in situ, in the ultra-high vacuum condition preventing any sample degradation. Three of them were selected to be characterized by XPS spectroscopy as well. Results. Among the organic residues presented in this paper, only those containing nitrogen and carbon exhibit the multi-component band centred at 2200 cm−1. This multi-component band presents interest from the astrobiological point of view due to its attribution to nitriles (–C≡N) and isonitriles (–N≡C). Our results demonstrate that this band is present in the IR spectra of organic nitrogen residues regardless the use of oxygen-bearing species in the icy mixture. This finding is of interest since the 2200 cm−1 band has been observed in some extraterrestrial samples (micro-meteorites) collected in the Antarctica.

Published
2018

13. GIADA performance during Rosetta mission scientific operations at comet 67P

Author

J. E. Rodriguez, V. Liuzzi, Stavro Ivanovski, V. Della Corte, Pasquale Palumbo, Simon F. Green, M. Cosi, S. Rotunno, M. Herranz, M. Ferrari, E. Mazzotta-Epifani, Marco Fulle, Mario Accolla, R. Morales, J. J. López-Moreno, Alessandra Rotundi, Luigi Colangeli, Ernesto Palomba, Roberto Sordini, ITA, GBR, ESP, NLD, and Agenzia Spaziale Italiana

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Rosetta ESA mission, Analyser, Comet, Aerospace Engineering, Astronomy and Astrophysics, Inflight calibration, GIADA, 01 natural sciences, Geophysics, Space and Planetary Science, 0103 physical sciences, Calibration, Dust instrument, General Earth and Planetary Sciences, Environmental science, Performance monitoring, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing
Abstract

The Grain Impact Analyser and Dust Accumulator (GIADA) instrument onboard Rosetta studied the dust environment of comet 67P/Churyumov–Gerasimenko from 3.7 au inbound, through perihelion, to 3.8 au outbound, measuring the dust flow and the dynamic properties of individual particles. GIADA is composed of three subsystems: (1) Grain Detection System (GDS); (2) Impact Sensor (IS); and (3) Micro-Balances System (MBS). Monitoring the subsystems’ performance during operations is an important element for the correct calibration of scientific measurements. In this paper, we analyse the GIADA inflight calibration data obtained by internal calibration devices for the three subsystems during the period from 1 August 2014 to 31 October 2015. The calibration data testify a nominal behaviour of the instrument during these fifteen months of mission; the only exception is a minor loss of sensitivity for one of the two GDS receivers, attributed to dust contamination.© 2017 COSPAR, Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI. We thank all the Rosetta instrument teams, the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. GIADA was built by a consortium led by the Univ. Napoli Parthenope & INAF - Oss. Astr. Capodimonte, in collaboration with the Inst. de Astrofisica de Andalucia, ES, Selex-FI-IT and SENER-ES. GIADA was managed and operated by Istituto di Astrofisica e Planetologia Spaziali-INAF, IT. GIADA was funded and managed by the Agenzia Spaziale Italiana, IT, with the support of the Spanish Ministry of Education and Science MEC, ES. GIADA was developed from a PI proposal from the University of Kent; sci. & tech. contributions were provided by CISAS, IT, Lab. d'Astr. Spat., FR, and Institutions from UK, IT, FR, DE and USA. Science support was provided by NASA through the US Rosetta Project managed by the Jet Propulsion Laboratory/California Institute of Technology. We would like to thank Angioletta Coradini for her contribution as a GIADA Co-I. GIADA calibrated data will be available through ESA's PSA web site (http://www.cosmos.esa.int/web/psa/rosetta).All data presented here are public. This research was supported by the Italian Space Agency (ASI) within the INAF-ASI agreements 1/032/05/0 and 1/024/12/0. The authors are grateful to the anonymous reviewers for very constructive suggestions that greatly contributed to improve our paper.

Published
2018

14. The dust-to-ices ratio in comets and Kuiper belt objects

Author

Stavro Ivanovski, V. V. Zakharov, Luigi Colangeli, Simon F. Green, Marco Fulle, Roberto Sordini, Alessandra Rotundi, V. Della Corte, M. Ferrari, Mario Accolla, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Universita degli studi di Napoli 'Parthenope' [Napoli], INAF - Osservatorio Astrofisico di Catania (OACT), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), INAF - Osservatorio Astronomico di Capodimonte (OAC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), ITA, GBR, FRA, NLD, Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Agence Spatiale Européenne = European Space Agency (ESA), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, Mass ratio, 01 natural sciences, Bulk density, 13. Climate action, Space and Planetary Science, Chondrite, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Comet 67P/Churyumov-Gerasimenko (67P hereinafter) is characterized by a dust transfer from the southern hemi-nucleus to the night-side northern dust deposits, which constrains the dust-to-ices mass ratio inside the nucleus to values a factor of 2 larger than that provided by the lost mass of gas and non-volatiles. This applies to all comets because the gas density in all night comae cannot prevent the dust fallback. Taking into account Grain Impact Analyser and Dust Accumulator (GIADA) data collected during the entire Rosetta mission, we update the average dust bulk density to ρD=785 +520/−115 $\rho {}{}_{\rm D} = 785_{-115}^{+520}$ kg m$^-3$ that, coupled to the 67P nucleus bulk density, confirms an average dust-to-ices mass ratio δ = 7.5 inside 67P. The improved dust densities are consistent with a mixture of (20 ± 8) per cent of ices, (4 ± 1) per cent of Fe sulphides, (22 ± 2) per cent of silicates and (54 ± 5) per cent of hydrocarbons, on average volume abundances. These values correspond to solar chemical abundances, as suggested by the elemental C/Fe ratio observed in 67P. The ice content in 67P matches that inferred in Kuiper belt objects, (20 ± 12) per cent on average volume abundance and suggests a water content in all trans-Neptunian objects lower than in CI chondrites. The 67P icy pebbles and the dust collected by GIADA have a microporosity of (49 ± 5) and (59 ± 8) per cent, respectively.

Published
2017
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15. Morphology of the solid water synthesized through the pathway D + O2 studied by the sensitive TPD technique

Author

Mario Accolla, Jean-Louis Lemaire, François Dulieu, E. Congiu, V. Pirronello, H. Chaabouni, G. Manicò, INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Catania = University of Catania (Unict), École normale supérieure - Paris (ENS Paris), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and Università degli studi di Catania [Catania]

Subjects
[PHYS]Physics [physics], Physics, Astrochemistry, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Hydrogen, 010308 nuclear & particles physics, Lead (sea ice), chemistry.chemical_element, Infrared spectroscopy, Astronomy and Astrophysics, 01 natural sciences, Amorphous solid, Deuterium, chemistry, Chemical engineering, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Amorphous ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Porosity, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract

We report on an experimental study on the formation of water, through the D + O2 pathway, on a sample of amorphous solid water, i.e. a realistic analogue of the surface of the interstellar grains of dense clouds. For improving our experimental conditions we use deuterium instead of hydrogen. We obtain, using both Temperature-Programmed Desorption Spectroscopy and Infrared Spectroscopy, that the morphology of the nascent water ice is mostly compact. We compare our results with those obtained previously by Oba et al. and show that the first technique is more effective in probing the morphology of amorphous water ice. We propose that the formation of compact ice is due to the heat of reactions which lead to the formation of water molecules. Water is synthesized, through the D + O2 pathway, on a film of compact amorphous solid water and on a porous substrate for comparison purposes. We show that in this latter case a gradual compaction of the sample takes place upon formation of new water molecules. We compare this reduction of water ice porosity with that one obtained by Accolla et al., due to recombination of deuterium atoms sent on the surface of an amorphous porous ice sample, and show that the compaction of the sample as a consequence of the water formation appears clearly more efficient.

Published
2013
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16. 67P/C-G Inner Coma dust properties from 2.2 au inbound to 2.0 au outbound to the Sun

Author

Mark Leese, Vito Mennella, Bo Å. S. Gustafson, Jean-François Crifo, Luigi Colangeli, M. Herranz, J. M. Jeronimo, Roberto Sordini, J. M. Perrin, Pasquale Palumbo, M. Cosi, V. Liuzzi, Simon F. Green, John C. Zarnecki, R. Rodrigo, Philippe Lamy, Alessandra Rotundi, Stavro Ivanovski, Eberhard Gruen, F. Moreno, J. E. Rodriguez, Vladimir Zakharov, P. Weissman, A. Molina, R. Morales, J. L. Ortiz, Ernesto Palomba, V. Della Corte, J. J. López-Moreno, F. J. M. Rietmeijer, E. Mazzotta Epifani, E. Bussoletti, M. Ferrari, J. A. M. McDonnell, A. Lopez-Jimenez, Marco Fulle, Mario Accolla, Francesca Esposito, F. Giovane, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), INAF - Osservatorio Astronomico di Trieste (OAT), Planetary and Space Sciences [Milton Keynes] (PSS), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU)-Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Department of Earth and Planetary Sciences [Albuquerque] (EPS), The University of New Mexico [Albuquerque], European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), INAF - Osservatorio Astrofisico di Catania (OACT), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Roma (OAR), Planetary Science Institute [Tucson] (PSI), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), HELIOS - 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), INAF - Osservatorio Astronomico di Capodimonte (OAC), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), University of Kent [Canterbury], Departamento de Fisica Aplicada [Granada], Universidad de Granada = University of Granada (UGR), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Leonardo, Virginia Polytechnic Institute and State University [Blacksburg], University of Florida [Gainesville] (UF), Universita degli studi di Napoli 'Parthenope' [Napoli], European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), HEPPI - LATMOS, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Universidad de Granada (UGR), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), University of Florida [Gainesville], The Open University [Milton Keynes] (OU), ITA, USA, GBR, FRA, DEU, and ESP

Subjects
010504 meteorology & atmospheric sciences, Comet dust, Dust particles, High density, Astrophysics, Spatial distribution, 01 natural sciences, Individual: 67P/Churyumov-Gerasimenko, Comet nucleus, 0103 physical sciences, 010303 astronomy & astrophysics, Instrumentation, 0105 earth and related environmental sciences, General-comets, Detectors-methods, Physics, comets: individual: 67P/Churyumov–Gerasimenko, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], instrumentation: detectors, comets: general, Astronomy, Astronomy and Astrophysics, methods: data analysis, Data analysis-comets, Space and Planetary Science, 13. Climate action, [SDU]Sciences of the Universe [physics], 67P/Churyumov-Gerasimenko [Individual], Space probe, Production rate
Abstract

GIADA (Grain Impact Analyzer and Dust Accumulator) on-board the Rosetta space probe is designed to measure the momentum, mass and speed of individual dust particles escaping the nucleus of comet 67P/Churyumov-Gerasimenko (hereafter 67P). From 2014 August to 2016 June, Rosetta escorted comet 67P during its journey around the Sun. Here, we focus on GIADA data taken between 2015 January and 2016 February which included 67P's perihelion passage. To better understand cometary activity and more specifically the presence of dust structures in cometary comae, we mapped the spatial distribution of dust density in 67P's coma. In this manner, we could track the evolution of high-density regions of coma dust and their connections with nucleus illumination conditions, namely tracking 67P's seasons. We also studied the link between dust particle speeds and their masses with respect to heliocentric distance, i.e. the level of cometary activity. This allowed us to derive a global and a local correlation of the dust particles' speed distribution with respect to the H2O production rate. © 2016 The Authors.

Published
2016
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17. Evolution of the Dust Size Distribution of Comet 67P/Churyumov–Gerasimenko from 2.2 au to Perihelion

Author

B. J. R. Davidsson, Nicolas Altobelli, Philippe Lamy, J. E. Rodriguez, Vladimir Zakharov, A. Molina, F. Lucarelli, Ivano Bertini, Ekkehard Kührt, R. Kramm, Bo Å. S. Gustafson, P. Weissman, Jose Luis Ortiz, Michael Küppers, Roberto Sordini, J. L. Bertaux, A. Lopez-Jimenez, Pasquale Palumbo, Alessandra Rotundi, J. J. López-Moreno, P. J. Gutiérrez, Mark Leese, Hans Rickman, J. M. Jeronimo, M. A. Barucci, E. Mazzotta Epifani, Monica Lazzarin, Jean-François Crifo, Stavro Ivanovski, Detlef Koschny, Nicolas Thomas, Vito Mennella, Eberhard Grün, Holger Sierks, Nilda Oklay, Carsten Güttler, M. De Cecco, K. P. Wenzel, Cesare Barbieri, F. Moreno, Stefano Mottola, Simon F. Green, Stubbe F. Hviid, Jean-Baptiste Vincent, Wing-Huen Ip, Laurent Jorda, Luisa Lara, V. Da Deppo, John C. Zarnecki, Mario Accolla, E. Bussoletti, Francesca Esposito, Francesco Marzari, M. L. Herranz, Sonia Fornasier, Jean-Marie Perrin, Luigi Colangeli, Jessica Agarwal, F. Giovane, M. Ferrari, Ernesto Palomba, Cecilia Tubiana, Giampiero Naletto, Marco Fulle, J. A. M. McDonnell, Dennis Bodewits, Jörg Knollenberg, V. Della Corte, Rafael Rodrigo, R. Morales, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, F. J. M. Rietmeijer, M. Cosi, Stefano Debei, Gabriele Cremonese, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Universita degli studi di Napoli 'Parthenope' [Napoli], Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig [Braunschweig], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), INAF - Osservatorio Astrofisico di Catania (OACT), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, European Space Astronomy Centre (ESAC), European Space Agency (ESA), 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), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Selex-ES, INAF - Osservatorio Astronomico di Padova (OAPD), HEPPI - LATMOS, CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Capodimonte (OAC), Virginia Polytechnic Institute and State University [Blacksburg], University of Florida [Gainesville], School of Physical Sciences [Milton Keynes], The Open University [Milton Keynes] (OU), Max-Planck-Institut für Kernphysik (MPIK), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), INAF - Osservatorio Astronomico di Roma (OAR), University of Kent [Canterbury], Departamento de Fisica Aplicada [Granada], Universidad de Granada (UGR), Department of Information Engineering [Padova] (DEI), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Department of Earth and Planetary Sciences [Albuquerque] (EPS), The University of New Mexico [Albuquerque], Physikalisches Institut [Bern], Universität Bern [Bern], Planetary Science Institute [Tucson] (PSI), Università degli Studi di Padova = University of Padua (Unipd), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), PLANETO - LATMOS, HELIOS - LATMOS, National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Florida [Gainesville] (UF), Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Universidad de Granada = University of Granada (UGR), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Universität Bern [Bern] (UNIBE), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)

Subjects
instruments [space vehicles], 010504 meteorology & atmospheric sciences, 530 Physics, Comet dust, Comet, Flux, comets: individual (67P/Churyumov-Gerasimenko), general, space vehicles: instruments, Astronomy and Astrophysics, Space and Planetary Science [comets], Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, GIADA, 01 natural sciences, general [comets], law.invention, Orbiter, Interplanetary dust cloud, law, Dust collector, Rosetta, 0103 physical sciences, Nadir, comets: general, Space and Planetary Science, OSIRIS, individual (67P/Churyumov-Gerasimenko) [comets], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], 520 Astronomy, Astronomy, Mass ratio, 620 Engineering, comet 67P/Churyumov–Gerasimenko, 13. Climate action, Astrophysics::Earth and Planetary Astrophysics
Abstract

The Rosetta probe, orbiting Jupiter-family comet 67P/Churyumov–Gerasimenko, has been detecting individual dust particles of mass larger than 10^(−10) kg by means of the GIADA dust collector and the OSIRIS Wide Angle Camera and Narrow Angle Camera since 2014 August and will continue until 2016 September. Detections of single dust particles allow us to estimate the anisotropic dust flux from 67P, infer the dust loss rate and size\ud distribution at the surface of the sunlit nucleus, and see whether the dust size distribution of 67P evolves in time.\ud The velocity of the Rosetta orbiter, relative to 67P, is much lower than the dust velocity measured by GIADA, thus\ud dust counts when GIADA is nadir-pointing will directly provide the dust flux. In OSIRIS observations, the dust\ud flux is derived from the measurement of the dust space density close to the spacecraft. Under the assumption of radial expansion of the dust, observations in the nadir direction provide the distance of the particles by measuring\ud their trail length, with a parallax baseline determined by the motion of the spacecraft. The dust size distribution at\ud sizes >1 mm observed by OSIRIS is consistent with a differential power index of −4, which was derived from\ud models of 67P’s trail. At sizes

Published
2016
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18. DENSITY AND CHARGE OF PRISTINE FLUFFY PARTICLES FROM COMET 67P/CHURYUMOV–GERASIMENKO

Author

Nicolas Altobelli, J. M. Jeronimo, Martin Hilchenbach, Philippe Lamy, Sihane Merouane, F. Lucarelli, M. Herranz, Mark Leese, Bo Å. S. Gustafson, M. Cosi, Stavro Ivanovski, Eberhard Grün, Vito Mennella, Jose Luis Ortiz, M. Ferrari, V. V. Zakharov, A. Lopez-Jimenez, Ernesto Palomba, Paul R. Weissman, Alessandra Rotundi, Roberto Sordini, Luigi Colangeli, R. Morales, J. E. Rodriguez, A. Molina, Mario Accolla, Francesca Esposito, V. Della Corte, Rafael Rodrigo, F. Giovane, J. A. M. McDonnell, J. J. López-Moreno, E. Mazzotta Epifani, Marco Fulle, John C. Zarnecki, Antal Juhász, F. Moreno, Pasquale Palumbo, E. Bussoletti, Simon F. Green, Karoly Szego, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Universita degli studi di Napoli 'Parthenope' [Napoli], Planetary Science Institute [Tucson] (PSI), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), Wigner Research Centre for Physics [Budapest], Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), INAF - Osservatorio Astronomico di Capodimonte (OAC), INAF - Osservatorio Astrofisico di Catania (OACT), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Max-Planck-Institut für Kernphysik (MPIK), British Geological Survey [Edinburgh], British Geological Survey (BGS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Leonardo, Virginia Polytechnic Institute and State University [Blacksburg], University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), European Space Astronomy Centre (ESAC), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and Agence Spatiale Européenne = European Space Agency (ESA)

Subjects
Physics, [PHYS]Physics [physics], Brightness, individual (67P/Churyumov-Gerasimenko) - space vehicles, Comet, Astronomy, Astronomy and Astrophysics, Coma (optics), general - comets, Astrophysics, Bulk density, 13. Climate action, Space and Planetary Science, instruments, comets, Negative potential, Formation and evolution of the Solar System, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Refractory (planetary science), ComputingMilieux_MISCELLANEOUS, Cosmic dust
Abstract

The Grain Impact Analyzer and Dust Accumulator (GIADA) instrument on board ESA’s Rosetta mission is constraining the origin of the dust particles detected within the coma of comet 67 P/Churyumov–Gerasimenko (67P). The collected particles belong to two families: (i) compact particles (ranging in size from 0.03 to 1 mm), witnessing the presence of materials that underwent processing within the solar nebula and (ii) fluffy aggregates (ranging in size from 0.2 to 2.5 mm) of sub-micron grains that may be a record of a primitive component, probably linked to interstellar dust. The dynamics of the fluffy aggregates constrain their equivalent bulk density to -3. These aggregates are charged, fragmented, and decelerated by the spacecraft negative potential and enter GIADA in showers of fragments at speeds -1. The density of such optically thick aggregates is consistent with the low bulk density of the nucleus. The mass contribution of the fluffy aggregates to the refractory component of the nucleus is negligible and their coma brightness contribution is less than 15%.

Published
2015
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19. Cometary science. Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the Sun

Author

Alessandra, Rotundi, Holger, Sierks, Vincenzo, Della Corte, Marco, Fulle, Pedro J, Gutierrez, Luisa, Lara, Cesare, Barbieri, Philippe L, Lamy, Rafael, Rodrigo, Detlef, Koschny, Hans, Rickman, Horst Uwe, Keller, José J, López-Moreno, Mario, Accolla, Jessica, Agarwal, Michael F, A'Hearn, Nicolas, Altobelli, Francesco, Angrilli, M Antonietta, Barucci, Jean-Loup, Bertaux, Ivano, Bertini, Dennis, Bodewits, Ezio, Bussoletti, Luigi, Colangeli, Massimo, Cosi, Gabriele, Cremonese, Jean-Francois, Crifo, Vania, Da Deppo, Björn, Davidsson, Stefano, Debei, Mariolino, De Cecco, Francesca, Esposito, Marco, Ferrari, Sonia, Fornasier, Frank, Giovane, Bo, Gustafson, Simon F, Green, Olivier, Groussin, Eberhard, Grün, Carsten, Güttler, Miguel L, Herranz, Stubbe F, Hviid, Wing, Ip, Stavro, Ivanovski, José M, Jerónimo, Laurent, Jorda, Joerg, Knollenberg, Rainer, Kramm, Ekkehard, Kührt, Michael, Küppers, Monica, Lazzarin, Mark R, Leese, Antonio C, López-Jiménez, Francesca, Lucarelli, Stephen C, Lowry, Francesco, Marzari, Elena Mazzotta, Epifani, J Anthony M, McDonnell, Vito, Mennella, Harald, Michalik, Antonio, Molina, Rafael, Morales, Fernando, Moreno, Stefano, Mottola, Giampiero, Naletto, Nilda, Oklay, José L, Ortiz, Ernesto, Palomba, Pasquale, Palumbo, Jean-Marie, Perrin, Julio, Rodríguez, Lola, Sabau, Colin, Snodgrass, Roberto, Sordini, Nicolas, Thomas, Cecilia, Tubiana, Jean-Baptiste, Vincent, Paul, Weissman, Klaus-Peter, Wenzel, Vladimir, Zakharov, and John C, Zarnecki

Abstract

Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency's Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10(-10) to 10(-7) kilograms, and 48 grains of mass 10(-5) to 10(-2) kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 ± 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.

Published
2015

20. GIADA: shining a light on the monitoring of the comet dust production from the nucleus of 67P/Churyumov Gerasimenko

Author

Antonio Molina, E. Bussoletti, M. Ferrari, Jose Luis Ortiz, Alessandra Rotundi, Mario Accolla, Luigi Colangeli, John C. Zarnecki, Francesca Esposito, Stavro Ivanovski, Bo Å. S. Gustafson, F. Giovane, Mark Leese, Simon F. Green, Jean-François Crifo, M. Herranz, J. J. Lopez-Moreno, V. Della Corte, P. L. Lamy, Roberto Sordini, Pasquale Palumbo, A. Lopez-Jimenez, Eberhard Gruen, F. Moreno, Vito Mennella, J. A. M. McDonnell, P.R. Weissmann, Ernesto Palomba, R. Morales, Marco Fulle, R. Rodrigo, V. Zakharov, J. M. Jeronimo, F. J. M. Rietmeijer, E. Mazzotta Epifani, J. M. Perrin, M. Cosi, F. Lucarelli, J. E. Rodriguez, Nicolas Altobelli, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), INAF - Osservatorio Astronomico di Trieste (OAT), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astrofisico di Catania (OACT), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Roma (OAR), INAF - Osservatorio Astronomico di Capodimonte (OAC), Instituto de Astrofsica de Andalucia, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), HELIOS - 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), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), University of Kent [Canterbury], The Open University [Milton Keynes] (OU), Departamento de Fisica Aplicada [Granada], Universidad de Granada = University of Granada (UGR), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Planetary Sciences [Albuquerque] (EPS), The University of New Mexico [Albuquerque], International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Selex-ES, Virginia Polytechnic Institute and State University [Blacksburg], University of Florida [Gainesville] (UF), European Space Astronomy Centre (ESAC), Spanish Ministry of Education and Science Ministerio de Educacion y Ciencias (MEC), NASA through the US Rosetta Project, Universita degli studi di Napoli 'Parthenope' [Napoli], Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), European Space Agency (ESA), HEPPI - LATMOS, Universidad de Granada (UGR), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), University of Florida [Gainesville], and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)

Subjects
Mass flux, 67P/Churyumov-Gerasimenko, Comet dust, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Instrumentation: detectors, Methods: data analysis, Space vehicles: instruments, Astronomy and Astrophysics, Space and Planetary Science, Comet nucleus, Comets, Circular orbit, Instrumentation, Astrophysics::Galaxy Astrophysics, Physics, Spacecraft, Comet tail, business.industry, Astronomy, Detectors, Space vehicles, Radiation pressure, 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business
Abstract

Context. During the period between 15 September 2014 and 4 February 2015, the Rosetta spacecraft accomplished the circular orbit phase around the nucleus of comet 67P/Churyumov-Gerasimenko (67P). The Grain Impact Analyzer and Dust Accumulator (GIADA) onboard Rosetta monitored the 67P coma dust environment for the entire period.\ud Aims. We aim to describe the dust spatial distribution in the coma of comet 67P by means of in situ measurements. We determine dynamical and physical properties of cometary dust particles to support the study of the production process and dust environment modification.\ud Methods. We analyzed GIADA data with respect to the observation geometry and heliocentric distance to describe the coma dust spatial distribution of 67P, to monitor its activity, and to retrieve information on active areas present on its nucleus. We combined GIADA detection information with calibration activity to distinguish different types of particles that populate the coma of 67P: compact particles and fluffy porous aggregates. By means of particle dynamical parameters measured by GIADA, we studied the dust acceleration region.\ud Results. GIADA was able to distinguish different types of particles populating the coma of 67P: compact particles and fluffy porous aggregates. Most of the compact particle detections occurred at latitudes and longitudes where the spacecraft was in view of the comet’s neck region of the nucleus, the so-called Hapi region. This resulted in an oscillation of the compact particle abundance with respect to the spacecraft position and a global increase as the comet moved from 3.36 to 2.43 AU heliocentric distance. The speed of these particles, having masses from 10-10 to 10-7 kg, ranged from 0.3 to 12.2 m s−1. The variation of particle mass and speed distribution with respect to the distance from the nucleus gave indications of the dust acceleration region. The influence of solar radiation pressure on micron and submicron particles was studied. The integrated dust mass flux collected from the Sun direction, that is, particles reflected by solar radiation pressure, was three times higher than the flux coming directly\ud from the comet nucleus. The awakening 67P comet shows a strong dust flux anisotropy, confirming what was suggested by on-ground dust coma observations performed in 2008.

Published
2015
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21. Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the sun

Author

F. Lucarelli, Roberto Sordini, Stavro Ivanovski, Vito Mennella, Hans Rickman, M. Ferrari, Michael F. A'Hearn, Mark Leese, Vincenzo Della Corte, Bo Å. S. Gustafson, E. Bussoletti, Luisa Lara, Jean-Loup Bertaux, M. Antonietta Barucci, Laurent Jorda, Rafael Rodrigo, Ernesto Palomba, Dennis Bodewits, Philippe Lamy, Detlef Koschny, Stefano Debei, Paul R. Weissman, J. Knollenberg, Francesco Marzari, Jean-François Crifo, Nilda Oklay, Nicolas Thomas, Stephen C. Lowry, Marco Fulle, Carsten Güttler, H. U. Keller, L. Sabau, K. P. Wenzel, J. E. Rodriguez, Michael Küppers, Vladimir Zakharov, A. Molina, Pedro J. Gutiérrez, Gabriele Cremonese, F. Giovane, Cesare Barbieri, Mario Accolla, Antonio C. López-Jiménez, Sonia Fornasier, Francesco Angrilli, Ekkehard Kührt, Francesca Esposito, Harald Michalik, José Juan López-Moreno, Elena Mazzotta Epifani, Vania Da Deppo, Jessica Agarwal, José M. Jerónimo, Fernando Moreno, Eberhard Grün, M. Cosi, Ivano Bertini, Olivier Groussin, R. Morales, Pasquale Palumbo, Simon F. Green, Stubbe F. Hviid, Jose Luis Ortiz, R. Kramm, Alessandra Rotundi, John C. Zarnecki, Giampiero Naletto, J. Anthony M. McDonnell, Wing Ip, Mariolino De Cecco, Colin Snodgrass, Stefano Mottola, Jean-Marie Perrin, Luigi Colangeli, Nicolas Altobelli, Monica Lazzarin, Jean-Baptiste Vincent, Björn Davidsson, Cecilia Tubiana, M. Herranz, Holger Sierks, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Akademie der Wissenschaften zu Göttingen, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Department of Industrial Engineering [Padova], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), HEPPI - LATMOS, CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), University of Trento [Trento], INAF - Osservatorio Astronomico di Capodimonte (OAC), Virginia Polytechnic Institute and State University [Blacksburg], University of Florida [Gainesville], School of Physical Sciences [Milton Keynes], The Open University [Milton Keynes] (OU), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], School of Physical Sciences [Canterbury], Institut für Datentechnik und Kommunikationsnetze, Departamento de Fisica Aplicada [Granada], Universidad de Granada (UGR), Department of Information Engineering [Padova] (DEI), Faculté d'Informatique [Namur], Facultés Universitaires Notre Dame de la Paix (FUNDP) - Namur, Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Instituto Nacional de Técnica Aeroespacial (INTA), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, HELIOS - LATMOS, University of Florida [Gainesville] (UF), Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Facultés Universitaires Notre Dame de la Paix (FUNDP), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universidad de Granada = University of Granada (UGR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU

Subjects
67P/Churyumov-Gerasimenko, genetic structures, Comet dust, Astronomical unit, comet 67P, coma, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, law.invention, Orbiter, comet, Planet, law, Rosetta, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Multidisciplinary, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Medicine (all), Astronomy, Mass ratio, Billion years, Accretion (astrophysics), 13. Climate action, Astrophysics::Earth and Planetary Astrophysics, dust, Formation and evolution of the Solar System
Abstract

Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency’s Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10 −10 to 10 −7 kilograms, and 48 grains of mass 10 −5 to 10 −2 kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 ± 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.

Published
2015
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22. Giada: its Status after the Rosetta Cruise Phase and On-Ground Activity in Support of the Encounter with Comet 67P/CHURYUMOV-GERASIMENKO

Author

Philippe Lamy, J. E. Rodriguez, F. Lucarelli, Simon F. Green, M. Ferrari, Jean-François Crifo, Roberto Sordini, Paul R. Weissman, R. Rodrigo, V. Mennella, A. C. López Jiménez, Stavro Ivanovski, A. Aronica, M. Herranz, J. M. Jeronimo, F. Moreno, Ernesto Palomba, Mario Accolla, Francesca Esposito, John C. Zarnecki, Luigi Colangeli, Pasquale Palumbo, J. A. M. McDonnell, F. J. M. Rietmeijer, Marco Fulle, E. Bussoletti, Eberhard Gruen, M. Cosi, J. M. Perrin, Alessandra Rotundi, J. J. Lopez-Moreno, R. Morales, V. Della Corte, V. Zakharov, E. Mazzotta Epifani, Antonio Molina, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Earth and Planetary Sciences [Albuquerque] (EPS), The University of New Mexico [Albuquerque], INAF - Osservatorio Astronomico di Capodimonte (OAC), HELIOS - 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), INAF - Osservatorio Astronomico di Trieste (OAT), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universita degli studi di Napoli 'Parthenope' [Napoli], European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), HEPPI - LATMOS, The Open University [Milton Keynes] (OU), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), California Institute of Technology (CALTECH)-NASA, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Physics, ESA Rosetta, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Cruise, Dust particles, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, GIADA, calibration, 01 natural sciences, dust instrument, Astrobiology, Outgassing, 13. Climate action, in flight data, 0103 physical sciences, business, 010303 astronomy & astrophysics, Instrumentation, 0105 earth and related environmental sciences
Abstract

GIADA (Grain Impact Analyser and Dust Accumulator) on-board the Rosetta mission to comet 67P/Churyumov-Gerasimenko was designed to study the physical and dynamical properties of dust particles ejected by the comet during the encounter. In this paper we report the results of the analysis of data collected by GIADA during the past seven years of the cruise phase. During this period the GIADA detection subsystems were switched on for periodic in-flight payload checkouts to monitor their state-of-health including potential changes in its performance that could affect its data collection. Only slight variations in sensitivity and dynamical range were identified that will not affect the GIADA measurement capability during the Rosetta comet encounter and rendezvous phase. The GIADA microbalance system detected the presence of low-volatility material over a period of about 169 days when the GIADA cover remained partially opened. It is highly probable that this material originated from the spacecraft itself, as a spacecraft's outgassing was observed by the ROSINA mass spectrometer (on-board Rosetta) during the cruise phase. The identification of the low-volatility mass deposited on the microbalances as self-contamination will allow us to evaluate the mass rate background to be subtracted from the GIADA science data. These results obtained from GIADA cruise data analysis coupled with laboratory calibration data obtained from measurements using the GIADA spare model for selected cometary dust analogs will be the basis for the interpretation of the GIADA scientific data.

Published
2014
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23. Quantum Tunneling of Oxygen Atoms on Very Cold Surfaces

Author

Stéphanie Cazaux, A. Moudens, V. Pirronello, S. Baouche, E. Congiu, Mario Accolla, H. Chaabouni, G. Manicò, Marco Minissale, François Dulieu, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Università degli studi di Catania = University of Catania (Unict), École normale supérieure - Paris (ENS Paris), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Università degli studi di Catania [Catania], and Astronomy

Subjects
AMORPHOUS SOLID WATER, MECHANISM, Astrochemistry, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Hydrogen, General Physics and Astronomy, chemistry.chemical_element, FOS: Physical sciences, 010402 general chemistry, Interactions of atoms and molecules with surfaces, Molecular and chemical processes and interactions, Atomic molecular and chemical and grain processes, NASCENT H-2, 01 natural sciences, Physics - Chemical Physics, 0103 physical sciences, Thermal, Diffusion (business), 010303 astronomy & astrophysics, Quantum, TEMPERATURE, Quantum tunnelling, ComputingMilieux_MISCELLANEOUS, Surface diffusion, Chemical Physics (physics.chem-ph), [PHYS]Physics [physics], Condensed Matter - Materials Science, DUST GRAINS, OZONE, Materials Science (cond-mat.mtrl-sci), Atmospheric temperature range, HYDROGEN, DIFFUSION, 0104 chemical sciences, chemistry, 13. Climate action, Chemical physics, MOBILITY, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], INTERSTELLAR GRAINS, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Any evolving system can change of state via thermal mechanisms (hopping a barrier) or via quantum tunneling. Most of the time, efficient classical mechanisms dominate at high temperatures. This is why an increase of the temperature can initiate the chemistry. We present here an experimental investigation of O-atom diffusion and reactivity on water ice. We explore the 6-25 K temperature range at sub-monolayer surface coverages. We derive the diffusion temperature law and observe the transition from quantum to classical diffusion. Despite of the high mass of O, quantum tunneling is efficient even at 6 K. As a consequence, the solid-state astrochemistry of cold regions should be reconsidered and should include the possibility of forming larger organic molecules than previously expected., Comment: 13 pages, 4 figures

Published
2013
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24. Publisher's Note: 'Water formation through O 2 + D pathway on cold silicate and amorphous water ice surfaces of interstellar interest' [J. Chem. Phys. 137, 234706 (2012)]

Author

François Dulieu, H. Chaabouni, J. L. Lemaire, V. Pirronello, M. Minissale, Jennifer A. Noble, Mario Accolla, S. Baouche, G. Manicò, E. Congiu, LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Catania [Catania], Institute of Biomedical Engineering [Oxford] (IBME), University of Oxford [Oxford], INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Metodologie Fisiche e Chimiche per l'Ingegneria, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Università degli studi di Catania = University of Catania (Unict), and University of Oxford

Subjects
[PHYS]Physics [physics], Astrochemistry, 010304 chemical physics, Interstellar ice, General Physics and Astronomy, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Oxygen, Silicate, 0104 chemical sciences, Astrobiology, Amorphous solid, chemistry.chemical_compound, chemistry, 0103 physical sciences, Formation water, Infrared cirrus, Physical and Theoretical Chemistry, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS, Cosmic dust
Abstract

International audience

Published
2013
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25. Water formation through O 2 + D pathway on cold silicate and amorphous water ice surfaces of interstellar interest: Water ice formation in the interstellar medium

Author

Marco Minissale, Mario Accolla, Jean-Louis Lemaire, H. Chaabouni, G. Manicò, E. Congiu, Jennifer A. Noble, François Dulieu, S. Baouche, V. Pirronello, LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Catania = University of Catania (Unict), INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), 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), the Conseil Régional d’Ile de France (SESAME Contract No. I- 07-597R), and the Conseil Général du Val d’Oise, French National PCMI program funded by the French National Center for Scientific Research (CNRS), ANR-07-BLAN-0129,IRHONI,Interaction et réactivité des atomes H, O et N sur des surfaces simulant les grains interstellaires à très basses températures(2007), and European Project: FP7

Subjects
Astrochemistry, Interstellar cloud, Analytical chemistry, General Physics and Astronomy, 02 engineering and technology, 01 natural sciences, chemistry.chemical_compound, Reactivity chemistry, 0103 physical sciences, Monolayer, Interstellar medium ISM, Physical and Theoretical Chemistry, Thermal desorption mass spectroscopy, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010303 astronomy & astrophysics, [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Interstellar ice, Silicate surface, Infrared spectroscopy IR RAIRS, 021001 nanoscience & nanotechnology, Silicate, Amorphous solid, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], Amorphous ice, Atomic physics, Absorption (chemistry), 0210 nano-technology
Abstract

International audience; The formation of the first monolayer of water molecules on bare dust grains is of primary importance to understand the growth of the icy mantles that cover dust in the interstellar medium. In this work, we explore experimentally the formation of water molecules from O 2 + D reaction on bare silicate surfaces that simulates the grains present in the diffuse interstellar clouds at visual extinctions (A V < 3 mag). For comparison, we also study the formation of water molecules on surfaces covered with amorphous water ice representing the dense clouds (A V ≥ 3 mag). Our studies focus on the formation of water molecules in the sub-monolayer and monolayer regimes using reflection absorption infrared spectroscopy and temperature-programmed desorption techniques. We provide the fractions of the products, such as D 2 O and D 2 O 2 molecules formed on three astrophysically relevant surfaces held at 10 K (amorphous olivine-type silicate, porous amorphous water ice, and nonporous amorphous water ice). Our results showed that the formation of D 2 O molecules occurs with an efficiency of about 55%-60% on nonporous amorphous water ice and about 18% on bare silicate grains surfaces. We explain the low efficiency of D 2 O water formation on the silicate surfaces by the desorption upon formation of certain products once the reaction occurs between O 2 and D atoms on the surface. A kinetic model taking into account the chemical desorption of newly formed water supports our conclusions.

Published
2012
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26. THE CATALYTIC ROLE OF CORONENE FOR MOLECULAR HYDROGEN FORMATION

Author

J. D. Thrower, Mario Accolla, Liv Hornekær, and Vito Mennella

Subjects
Physics, Astrochemistry, Hydrogen, Absorption spectroscopy, astrochemistry, Infrared spectroscopy, chemistry.chemical_element, Astronomy and Astrophysics, 010402 general chemistry, Photochemistry, 01 natural sciences, Coronene, 0104 chemical sciences, chemistry.chemical_compound, Deuterium, chemistry, Space and Planetary Science, 0103 physical sciences, Atom, Molecule, Atomic physics, laboratory, 010303 astronomy & astrophysics
Abstract

We present the results of an experimental study on the interaction of atomic deuterium with coronene films. The effects of D atom irradiation have been analyzed with infrared spectroscopy. The spectral changes provide evidence for deuteration of the outer edge coronene C sites via a D addition reaction. A cross section of 1.1Å2 is estimated for the deuteration process of coronene. HD and D2 molecules form, through abstraction reactions, on deuterated coronene sites with a cross section of 0.06Å2. The magnitude of both cross sections is in line with an Eley–Rideal type process. The results showthat hydrogenated neutral polycyclic aromatic hydrocarbon molecules act as catalysts for the formation of molecular hydrogen.

Published
2011
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27. Changes in the morphology of interstellar ice analogues after hydrogen atom exposure

Author

François Dulieu, Mario Accolla, E. Congiu, J. L. Lemaire, H. Mokrane, Valerio Pirronello, E. Matar, H. Chaabouni, G. Manicò, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Molécules dans l'Univers, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), and Università degli studi di Catania = University of Catania (Unict)

Subjects
Morphology (linguistics), Hydrogen, Compaction, General Physics and Astronomy, chemistry.chemical_element, FOS: Physical sciences, Astrophysics, Physics::Geophysics, Irradiation, Physical and Theoretical Chemistry, Porosity, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, Physics, Accretion (meteorology), Molecular cloud, Interstellar ice, Lead (sea ice), General Engineering, Astronomy and Astrophysics, Hydrogen atom, Astrophysics - Astrophysics of Galaxies, Amorphous solid, Interstellar medium, chemistry, Space and Planetary Science, Chemical physics, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], human activities
Abstract

The morphology of water ice in the interstellar medium is still an open question. Although accretion of gaseous water could not be the only possible origin of the observed icy mantles covering dust grains in cold molecular clouds, it is well known that water accreted from the gas phase on surfaces kept at 10 K forms ice films that exhibit a very high porosity. It is also known that in the dark clouds H2 formation occurs on the icy surface of dust grains and that part of the energy (4.48 eV) released when adsorbed atoms react to form H2 is deposited in the ice. The experimental study described in the present work focuses on how relevant changes of the ice morphology result from atomic hydrogen exposure and subsequent recombination. Using the temperature-programmed desorption (TPD) technique and a method of inversion analysis of TPD spectra, we show that there is an exponential decrease in the porosity of the amorphous water ice sample following D-atom irradiation. This decrease is inversely proportional to the thickness of the ice and has a value of Phi_0 = 2 x 10^16 D-atoms/cm^2 per layer of H2O. We also use a model which confirms that the binding sites on the porous ice are destroyed regardless of their energy depth, and that the reduction of the porosity corresponds in fact to a reduction of the effective area. This reduction appears to be compatible with the fraction of D2 formation energy transferred to the porous ice network. Under interstellar conditions, this effect is likely to be efficient and, together with other compaction processes, provides a good argument to believe that interstellar ice is amorphous and non-porous., Comment: 9 pages, 7 figures, submitted to PCCP

Published
2010
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28. Experimental Evidence for Water Formation Via Ozone Hydrogenation on Dust Grains at 10 K

Author

E. Congiu, H. Chaabouni, H. Mokrane, J. L. Lemaire, M. Chehrouri, Mario Accolla, François Dulieu, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Catania = University of Catania (Unict), and Université de Saïda

Subjects
Physics, Ozone, Analytical chemistry, Mixing (process engineering), Substrate (chemistry), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Amorphous solid, chemistry.chemical_compound, chemistry, Space and Planetary Science, Desorption, Astrophysics of Galaxies (astro-ph.GA), Molecule, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Order of magnitude, Cosmic dust
Abstract

The formation of water molecules from the reaction between ozone (O3) and D-atoms is studied experimentally for the first time. Ozone is deposited on non-porous amorphous solid water ice (H2O), and D-atoms are then sent onto the sample held at 10 K. HDO molecules are detected during the desorption of the whole substrate where isotope mixing takes place, indicating that water synthesis has occurred. The efficiency of water formation via hydrogenation of ozone is of the same order of magnitude of that found for reactions involving O atoms or O2 molecules and exhibits no apparent activation barrier. These experiments validate the assumption made by models using ozone as one of the precursors of water formation via solid-state chemistry on interstellar dust grains., Comment: 16 pages, 2 figures, to be published on ApJL

Published
2009
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29. Formation of water on silicate surfaces under interstellar conditions

Author

S. Baouche, Jean-Louis Lemaire, Mario Accolla, François Dulieu, H. Chaabouni, E. Congiu, Marco Minissale, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Molécules dans l'Univers, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), and Dipartimento di Scienze Applicate, Università Parthenope di Napoli

Subjects
Physics, Interstellar cloud, General Engineering, Astronomy and Astrophysics, Astrophysics, Silicate, Amorphous solid, chemistry.chemical_compound, chemistry, Space and Planetary Science, Chemical physics, Molecule, Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We explore experimentally the formation of water molecules from O2 and D atoms on bare grains composed of amorphous silicates analogous to those in diffuse interstellar clouds. We provide the fractions of D2O and D2O2 molecules formed on the silicate surface held at 10 K from the O2 D pathway using RAIRS and TPD techniques. For comparison, we also study the formation of water molecules on surfaces covered with amorphous water ice representing the dense clouds.

Published
2012
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30. Gas temperature dependent sticking of hydrogen on cold amorphous water ice surfaces of interstellar interest

Author

E. Matar, J. L. Lemaire, François Dulieu, Mario Accolla, H. Chaabouni, H. Bergeron, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires d'Orsay (ISMO), and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Hydrogen, Surface Properties, FOS: Physical sciences, General Physics and Astronomy, chemistry.chemical_element, Thermodynamics, 010402 general chemistry, 01 natural sciences, Physics - Chemical Physics, 0103 physical sciences, Physics::Atomic Physics, Physical and Theoretical Chemistry, Porosity, 010303 astronomy & astrophysics, Chemical Physics (physics.chem-ph), Thermal equilibrium, Models, Statistical, Hydrogen molecule, Temperature, Water, Deuterium, 0104 chemical sciences, Amorphous solid, chemistry, Gases, Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Beam (structure)
Abstract

International audience; Using the King and Wells method, we present experimental data on the dependence of the sticking of molecular hydrogen and deuterium on the beam temperature onto nonporous amorphous solid water ice surfaces of interstellar interest. A statistical model that explains the isotopic effect and the beam temperature behavior of our data is proposed. This model gives an understanding of the discrepancy between all known experimental results on the sticking of molecular hydrogen. Moreover, it is able to fit the theoretical results of Buch et al. [Astrophys. J. 379, 647 (1991)] on atomic hydrogen and deuterium. For astrophysical applications, an analytical formula for the sticking coefficients of H, D, H2, D2, and HD in the case of a gas phase at thermal equilibrium is also provided at the end of the article.

Published
2010
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