Radiolysis of Amino Acids by Heavy and Energetic Cosmic Ray Analogs in Simulated Space Environments: α\alpha-Glycine Zwitterion Form

In this work, we studied the stability of the glycine molecule in the crystalline zwitterion form, known as {\alpha}-glycine ($^{+}$NH$_{3}$CH$_{2}$COO$^{-}$) under action of heavy cosmic ray analogs. The experiments were conducted in a high vacuum chamber at heavy ions accelerator GANIL, in Caen, France. The samples were bombarded at two temperatures (14 K and 300 K) by $^{58}$Ni$^{11+}$ ions of 46 MeV until the final fluence of $10^{13}$ ions cm$^{-2}$. The chemical evolution of the sample was evaluated in-situ using Fourrier Transformed Infrared (FTIR) spectrometer. The bombardment at 14 K produced several daughter species such as OCN$^-$, CO, CO$_2$, and CN$^-$. The results also suggest the appearing of peptide bonds during irradiation but this must be confirmed by further experiments. The halflives of glycine in Interstellar Medium were estimated to be 7.8 $\times 10^3$ years (300 K) and 2.8 $\times 10^3$ years (14 K). In the Solar System the values were 8.4 $\times 10^2$ years (300 K) and 3.6 $\times 10^3$ years (14 K). It is believed that glycine could be present in space environments that suffered aqueous changes such as the interior of comets, meteorites and planetesimals. This molecule is present in proteins of all alive beings. So, studying its stability in these environments provides further understanding about the role of this specie in the prebiotic chemistry on Earth.Comment: 28 pages, 12 figures, 9 tables. Accepted to be published at Monthly Notices of the Royal Astronomical Society (MNRAS

Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System

Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc.) of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone) after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.This research has been supported by the European COST Action CM0805: The Chemical Cosmos.Boduch, P.; Da Silveira, EF.; Domaracka, A.; Gomis Hilario, O.; Lv, XY.; Palumbo, ME.; Pilling, S.... (2011). Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System. Advances in Astronomy. 1-10. doi:10.1155/2011/327641S11

Etude par spectroscopie infrarouge des effets d'irradiation de glaces d'intérêt astrophysique par des ions lourds

Dans le système solaire et dans les régions denses du milieu interstellaire, des manteaux de glaces constitués de petites molécules sont irradiés par des particules ionisantes : des photons, des électrons et des ions. L interaction entre les particules énergétiques et les manteaux induit plusieurs processus tels que les réactions chimiques, les changements de phase et la désorption de molécules. Les effets de l irradiation par des photons et des ions légers sont étudiés depuis 20 ans. Cependant, les expériences réalisées avec des ions lourds et rapides sont rares dans la littérature. Bien que les ions légers soient plus abondants, le grand pouvoir d arrêt et le haut rendement de pulvérisation des ions lourds peuvent compenser cet écart numérique. Ce travail résulte d un projet de collaboration entre la PUC-Rio et le CIMAP-GANIL. L objectif de ce projet est d étudier l effet de l irradiation de glaces astrophysiques avec des ions lourds et rapides. Les expériences ont été réalisées sur les lignes IRRSUD et SME du GANIL avec des ions Ni (46 et 537 MeV). L analyse des glaces a été faite par spectroscopie infrarouge par transformée de Fourier (FTIR). Quatre cibles ont été irradiées et analysées : H2O, CO, CO2 et H2O :CO :NH3. Les sections efficaces de destruction, de création des molécules produites et les rendements de pulvérisation ont été déterminés pour chaque cible. Les résultats obtenus montrent que les ions lourds sont plus efficaces que les protons pour la pulvérisation des manteaux de glaces alors que les protons sont eux plus efficace pour la synthèse de nouvelles molécules.In the Solar System, as well as inside the dense interstellar regions, ice mantles constituted by small molecules are exposed to ionizing radiation formed by photons, electrons and ions. As a result, chemical reactions, phase changes, desorption and other physical chemical processes occur in the ice. Among the ionizing projectiles, fast heavy ions play a particular role in the sense that they are relatively low abundant in space but have high ionizing power and are very efficient for inducing desorption. These cosmic events can be simulated in laboratory. The main goal of the current work is to identify and quantify the effects of the fast heavy ion interaction with ices. Experiments were performed at the medium energy facility at GANIL, where 46 and 537 MeV Ni ions irradiated four ices cooled down at about 13 K: H2O, CO, CO2 and the mixture H2O:NH3:CO. The molecular concentrations of these species and the formed ones were determined by infrared spectroscopy (FTIR) as a function of the beam fluence. From the acquired data, destruction and formation cross sections of molecular species were measured as well as the sputtering yields. Results show that protons are more efficient for producing new molecular species, while heavy ions are responsible for the desorption process. This work is collaboration between the PUC-Rio and CIMAP-GANIL institutions.CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Sulfur ion irradiation experiments simulating space weathering of Solar System body surfaces: Organosulfur compound formation

International audienceContext. Sulfur (S) is of prime interest in the context of (astro)chemical evolution and habitability. However, the origin of S-bearing organic compounds in the Solar System is still not well constrained.Aims. We carried out laboratory experiments to test whether complex organosulfur compounds can be formed when surfaces of icy Solar System bodies are subject to high-energy S ions.Methods. Non-S-bearing organic residues, formed during the processing of astrophysical H2O:CH3OH:NH3-bearing ice analogs, were irradiated with 105 keV-S7+ ions at 10 K and analyzed by high-resolving FT-ICR-MS. The resulting data were comprehensively analyzed, including network analysis tools.Results. Out of several thousands of detected compounds, 16% contain at least one sulfur atom (organosulfur (CHNOS) compounds), as verified via isotopic fine structures. These residue-related organosulfur compounds are different from those formed during the S ion irradiation of ices at 10 K. Furthermore, insoluble, apolar material was formed during the sulfur irradiation of residues. Potential organosulfur precursors (CHNO molecules) were identified by means of molecular networks.Conclusions. This evidence of organosulfur compounds formed by sulfur irradiation of organic residues sheds new light onto the rich and complex scope of pristine organosulfur chemistry in the Solar System, presented in the context of current and future space missions. These results indicate that the space weathering of Solar System bodies may lead to the formation of organosulfur compounds

Energetic Processing of N 2 :CH 4 Ices Employing X-Rays and Swift Ions: Implications for Icy Bodies in the Outer Solar System

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RADIÓLISE DE AMINOÁCIDO SOB AÇÃO DE ÍONS PESADOS: IMPLICAÇÕES EM ASTROQUÍMICA E ASTROBIOLOGIA

Neste trabalho, estudamos a estabilidade da molécula de glicina na sua forma zwiteriônica cristalina, conhecida como a-glycina (+NH3CH2COO-) a duas temperaturas (14 e 300 K), sob a ação de íons rápidos, simulando ambientes espaciais na presença de raios cósmicos pesados. Para tanto, a meia vida da glicina bombardeada no meio interestelar (nuvens densas) foi estimada, sendo 1.1 x 104 anos (300 K) e 1.6 x 103 anos (14 K). No sistema solar, os valores foram de 1.2 x 103 anos (300 K) e 2.8 x 103 anos (14 K). O estudo da estabilidade da glicina, nesses ambientes, traz à tona questões sobre o papel dessa molécula na química pré-bióticana Terra, para auxiliar nas descobertas sobre a origem da vida como a conhecemos

Can sulfur implantation in interstellar ice analogs lead to the formation of sulfur-bearing organics?

International audienceWe present the results of the irradiation of interstellar ice analogs (H 2 O:NH 3 :CH 3 OH) with argon and sulfur energetic ions. The samples were generated and irradiated at 10 K, and were thick enough to ensure the projectiles were implanted in the ice, allowing the sulfur projectiles to become part of the ensuing chemistry. The samples were measured on-site with Fourier Transform Infra-Red (FT-IR) spectroscopy, and the organic residues were analyzed off-site through Very High Resolution Mass Spectrometry (VHRMS). The IR spectra did not reveal any difference between the Ar-irradiated and S-irradiated samples, but the VHRMS allowed to investigate the potential formation of sulfur-bearing organic compounds

Can sulfur implantation in interstellar ice analogs lead to the formation of sulfur-bearing organics?

International audienceWe present the results of the irradiation of interstellar ice analogs (H 2 O:NH 3 :CH 3 OH) with argon and sulfur energetic ions. The samples were generated and irradiated at 10 K, and were thick enough to ensure the projectiles were implanted in the ice, allowing the sulfur projectiles to become part of the ensuing chemistry. The samples were measured on-site with Fourier Transform Infra-Red (FT-IR) spectroscopy, and the organic residues were analyzed off-site through Very High Resolution Mass Spectrometry (VHRMS). The IR spectra did not reveal any difference between the Ar-irradiated and S-irradiated samples, but the VHRMS allowed to investigate the potential formation of sulfur-bearing organic compounds

Acetone degradation by cosmic rays in the solar neighbourhood and in the Galactic Centre

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Laboratory simulation of heavy-ion cosmic-ray interaction with condensed CO

International audienceContext. Within dense interstellar clouds, from their periphery to regions deep inside, ice mantles on dust grains are exposed to cosmic-ray irradiation. Various swift ions contribute from protons to iron in the keV to TeV energy range. Observations show that in some lines of sight condensed CO molecules are an important component of the ice. Aims. We irradiate CO ices with Ni ions of relatively high energy (50 and 537 MeV) to simulate the effects produced by fast heavy cosmic-ray ions in interstellar grain mantles. Methods. CO gas is condensed on a CsI substrate at 13 K and irradiated by 50 MeV 58Ni13+ and 537 MeV 64Ni24+ ions up to a final fluence of ≈1 × 1013 cm−2, at a flux of 1 × 109 cm−2 s−1. The sputtering yields, the destruction rate of CO, and the rate of formation of new molecular species are measured in situ by Fourier transform infrared spectroscopy (FTIR). Results. The measured CO destruction cross-sections and sputtering yields induced by Ni ions are, respectively, (i) for 50 MeV, σd = 1.0×10−13 cm2 and Y = 7×104 molecules/impact; (ii) for 537 MeV, σd = 3.0×10−14 cm2 and Y = 5.85×104 molecules/impact. Based on the present and previous results, the desorption rates induced by H, Ni, and Fe ions are estimated for a wide range of energies. The contribution of the heavy ions is found to dominate over that of protons in the interstellar medium