STELLAR WIND-INDUCED SOLID-STATE REACTIONS - A MECHANISM OF ORGANIC-SYNTHESIS IN-SPACE

The bombardment of carbonaceous dust species by ions of stellar wind and the role of this effect in the formation and evolution of organic matter in interstellar medium and solar system was studied in laboratory experiments. Evidence was obtained that solid-state organic synthesis may proceed directly from inorganic reagents irradiated by keV-energy ions. The surface of a graphite powder irradiated at a temperature of 300 K by H+, He+, and N+ ions of a 10-keV energy exhibits the formation of polycyclic aromatic hydrocarbons (PAH), the class of organic molecules that is one of the most widely occurring in space. It s concluded that radiation-induced formation of PAH may take place on the surface of carbon-containing dust species in the near-stellar medium exposed to the flux of accelerated protons emitted from the nearest star. The flux provides both matter and energy necessary for the formation of C-H bonds. A mechanism is proposed that can explain the amount of PAH observed in the interstellar medium.