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new publication: Photochemistry of Coronene in CosmicAbstract:This work presents the photochemistry of ultraviolet (UV) irradiated coronene in water ices at 15K studied using mid-infrared Fourier transform (FTIR) spectroscopy for C24H12:H2O at concentrations of (1:50), (1:150), (1:200), (1:300), and (1:400). Previous UV irradiation studies of anthracene:H2O, pyrene:H2O, and benzo[ghi]perylene:H2O ices at 15 K have shown that aromatic alcohols and ketones, as well as CO2 and H2CO, are formed at very low temperatures. Likewise, here, in addition to the coronene cation, hydroxy-, keto-, and protonated coronene (coronene H+) are formed. The rate constants for the decay of neutral coronene and for the formation of photoproducts have been derived. It is shown that Polycyclic Aromatic Hydrocarbons (PAHs) and their UV induced PAH:H2O photoproducts have mid-infrared spectroscopic signatures in the 5–8 μm region that can contribute to the interstellar ice components described by Boogert et al. as C1–C5. Our results suggest that oxygenated and hydrogenated PAHs could be in UV-irradiated regions of the interstellar medium where water-rich ices are important.

Important Note: This research is the result of a visiting researcher, Dr. Ana Ferreira de Barros, who was sponsored by The Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) program. The work was carried in Dr. Andrew Mattioda’s laboratory under research sponsored under the NASA Astrobiology Institute (CAN 7) Ames grant.  This work is in alignment with agreements, signed in 2015, between NASA and the Brazilian Space Agency (AEB) to enhance collaborations and educational opportunities between the agencies.



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