Detection of Simulated Space Weathering on Electron Irradiated Water-Ice Coated Silicon Using AFM-IR, SEM, and S/TEM Techniques
Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Space weathering causes physical and spectral changes on the surfaces of airless bodies. However, our understanding of how space weathering operates in the presence of volatile ices is in its early stages. Electron irradiation of ice-coated surfaces is expected in astrophysical environments including the early solar system, volatile ice-rich permanently shadowed regions of the Moon and Mercury, and other airless bodies like asteroids. A recent study suggests that anomalous oxygen isotope exchange occurs between water-ice and underlying surfaces when exposed to electron irradiation at extremely low temperatures (10 K). To delve deeper into the physical processes underlying isotopic exchange, we employ nanoscale atomic force microscopy-based infrared (AFM-IR) spectroscopy to identify Si–O bond formation resulting from the electron irradiation of H 2 O ice coated silicon targets. Experimental variables include electron energy, amount and timing of water-ice deposition, and surface area exposed to the electron beam. AFM-IR point spectra, surface topography and IR absorption mapping reveal that the degree of surface oxidation is dependent upon experimental conditions. Scanning electron microscopy and (scanning) transmission electron microscope imaging confirm the formation of thicker SiO x in regions of enhanced interaction between electron irradiation, water-ice, and the silicon substrate. In summary, we find that electron irradiation with energies as low as 1 keV/electron can break the chemical bonds of refractory solids like Si under these simulated cold astrophysical conditions. These results suggest that cosmic rays may play a more significant role than previously thought in the chemical evolution of dust grains in cold astrophysical and protoplanetary environments.
Source: ACS Earth and Space Chemistry
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: G1286236842, G1286251239, G1632040200, G1863003419, G2885761848, G30714459, G3083819904, G4501827968, G498139845, MULTI-ISOTOPIC MEASUREMENTS OF OZONE FORMATION ON INTERSTELLAR DUST GRAIN ANALOGSDECADES OF MULTI-OXYGEN ISOTOPIC MEASUREMENTS OF PLANETARY MATERIALS HAVE SHOWN THAT THE DISTRIBUTION OF OXYGEN ISOTOPES IN THE SOLAR SYSTEM IS ANOMALOUS AND CANNOT BE EXPLAINED BY CONVENTIONAL MASS-DEPENDENT ISOTOPIC FRACTIONATION PROCESSES. BECAUSE OF THE CENTRAL IMPORTANCE THAT OXYGEN HAS AS BOTH A REFRACTORY AND VOLATILE ELEMENT UNDERSTANDING THE PHYSICAL-CHEMICAL PROCESSES RESPONSIBLE FOR THE DISTRIBUTION OF OXYGEN ISOTOPES IN THE SOLAR SYSTEM AS REVEALED BY STUDIES OF METEORITES AND THE GENESIS MISSION IS ESSENTIAL FOR ADVANCING OUR UNDERSTANDING OF THE FORMATION AND EVOLUTION OF THE SOLAR SYSTEM. BASED ON THE WELL-KNOWN MASSINDEPENDENT OXYGEN ISOTOPE EFFECT OF OZONE IN THE GAS-PHASE IT WAS RECENTLY PROPOSED THAT THE FORMATION OF OZONE A LIKELY PRECURSOR TOWATER ON COLD DUST GRAINS IN DENSE MOLECULAR CLOUDS MAY BE RESPONSIBLE FOR THE ANOMALOUS DISTRIBUTION OF OXYGEN ISOTOPES IN THE SOLAR SYSTEM. HERE WE PROPOSE SYSTEMATIC LABORATORY STUDIES OF OZONE FORMATION ON COLD DUST GRAIN SURFACES TO TEST THE HYPOTHESIS THAT DUST GRAIN PHOTOCHEMISTRY MAY BE RESPONSIBLE FOR THE MASS-INDEPENDENT DISTRIBUTIONS OF OXYGEN ISOTOPES IN THE SOLAR SYSTEM., G650090426, G6652958823, RUI: Resolving Astrophysical Water Formation Pathways on Dust Grain Surfaces, G969889393
OpenAlex ID: W7166355780