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Tem arquivos: true × Assunto: Astrobiology ×

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    Methylenimine and cyanomethanimine synthesis from ion irradiation of N2-CH4 ice: Implication on the formation of prebiotic molecules in outer solar system bodies
    (Elsevier) Vasconcelos, Fredson de Araujo; Pilling, Sergio; Agnihotri, Aditya Narain; Rothard, Hermann; Boduch, Philippe
    The synthesis of methylenimine and cyanomethanimine from ion irradiation of N2-CH4 ice was studied, in an attempt to simulate the role of medium mass cosmic rays and energetic solar particles in the processing of nitrogen-rich ices on cold astrophysical environments, such as those in the outer region of the solar system (e.g. Pluto, Charon, Triton, Makemake and Titan). The N2-CH4 (90:10) ice mixture was irradiated at 9 K by 38.4 MeV 40Ca9+ (0.96 MeV/u) at the GANIL facility (Caen/Fance). The evolution of the samples was monitored using in-situ Fourier transform infrared spectroscopy (FTIR). The results indicate the formation of CH2NH and CH2NCN, which are considered species of interest in prebiotic chemistry. Other species produced by radiolysis were HCN, HNC, hydrocarbons and nitriles. Direct comparison of the laboratory spectrum from the mixture of reaction products provides an efficient way to focus on the identification of chemical synthesis routes for the production of molecules important in the development of life that are consistent with the chemical inventory and physical conditions on frozen moons and cold objects in the outer solar system.
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    Cosmic fertilization? Implantation of astrobiologically relevant cosmic rays in molecular clouds
    (Elsevier) Pilling, Sergio; Pazianotto, Maurício Tizziani
    This study investigates the implantation of astrobiologically relevant elements (e.g., carbon (C), oxygen (O), nitrogen (N), sulfur (S) and phosphorus (P)) into molecular clouds induced by cosmic rays. Using the Monte Carlo toolkit Geant4, we simulated the interaction of incoming high-energy protons and alpha particles with a mo- lecular clump characterized by a centrally concentrated density profile and a mass of approximately 30 M⊙. The results reveal a spatial gradient in implantation rates, with the highest rates occurring in the central regions due to increased target densities and reduced projectile energy. Protons (p) dominate the implantation process across all regions, followed by O, C, N, S, and P, with element-specific implantation efficiencies varying with distance from the clump center. This research identified regions inside the molecular cloud with distinct domains of atomic implantation enrichment with implications for astrobiology. The region at ∼1 AU exhibits the interesting atom implantation enrichment of the studied atoms, making it particularly significant for the formation of complex organic molecules. The findings highlight the importance of cosmic ray interactions in selectively enriching specific regions of molecular clouds with astrobiologically essential elements.