New center article - Ko-Ju Chuang
Title: Interstellar Carbonaceous Dust Erosion Induced by X-Ray Irradiation of Water Ice in Star-forming Regions
This work presents a quantitative and microscopic study of the carbonaceous dust grain erosion induced by soft X-ray irradiation (250-1250 eV) of interstellar water ice analogs under protoplanetary disk conditions. The physicochemical interactions between H2O ice and dust surfaces are systematically investigated using isotope-labeled oxygen/carbon species in kinetic analysis to better understand the interface reactions between ice and carbon grains. Experimental results prove that surface erosion proceeds by double oxygen atom additions to grain surfaces, forming CO2, which further dissociates and forms CO. The study suggests an additional route for converting refractory material to volatile carbonaceous species, which are precursors for several interstellar organics, enriching the chemical inventory of protoplanetary midplanes.