Year: 2026
Type: article
Abstract: The chemical evolution of CH4:CO2:NH3 astrophysical ice analogs was investigated under irradiation by 538 MeV 64Ni24+ ions at 14 K, simulating the effects of heavy cosmic rays in dense interstellar environments. Molecular changes were monitored in situ using Fourier transform infrared (FTIR) spectroscopy. A progressive depletion of the precursor species was observed with increasing ion fluence, accompanied by the formation of a diverse set of products, including CO, H2O, C2H6, C2H4, CH3OH, H2CO, HCOOH, HCOO–, OCN–, and N2O. The evolution of column densities revealed an initial rapid growth phase followed by saturation, reflecting the competition between formation and destruction processes. Destruction and formation cross sections were derived assuming first-order kinetics, and the corresponding radiochemical yields were determined. CO exhibited the highest formation yield, indicating that CO2 dissociation is one of the dominant irradiation-induced processes, while the efficient production of CH3OH, H2CO, OCN–, and N2O demonstrated the simultaneous operation of carbon-, oxygen-, and nitrogen-bearing reaction pathways. An atomic budget analysis indicated that a significant fraction of dissociated atoms was not accounted for in the observed infrared-active species, suggesting the formation of more complex or refractory compounds. These findings demonstrate the key role of heavy-ion processing in driving chemical complexity in interstellar ices, promoting the formation of oxygen- and nitrogen-bearing organic species of astrochemical and prebiotic relevance.
Source: ACS Earth and Space Chemistry
Institutions: Centre National de la Recherche Scientifique, Federal Center for Technological Education Celso Suckow da Fonseca, École Nationale Supérieure d'Ingénieurs de Caen, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Centre de Recherche sur les Ions, les Matériaux et la Photonique, Université de Caen Normandie, Universidade Federal da Bahia, Pontifícia Universidade Católica do Rio de Janeiro
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: Agence Nationale de la Recherche, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos, Central Institute of Medicinal and Aromatic Plants
OpenAlex ID: W7172414905