Astrophysics and Space Sciences Transactions www.astrophys-space-sci-trans.net 1810-6528 1810-6536 4 2 2008 10.5194/astra-4-47-2008 http://www.astrophys-space-sci-trans.net/4/47/2008/ http://www.astrophys-space-sci-trans.net/4/47/2008/astra-4-47-2008.html http://www.astrophys-space-sci-trans.net/4/47/2008/astra-4-47-2008.pdf 47 50 2008-10-15 Theoretical investigation of cosmic ray processing of solar system ices A. G. Yeghikyan arayeg@web.am Byurakan Astrophysical Observatory, Byurakan, 0433, Armenia Space ices containing water, carbon- and nitrogen-rich structures are important in certain chemical and radiation induced processes in Solar System dust systems. Up to now there are no detailed investigations on an energetic particle processing of various ices by ions and electrons, modeling the cosmic ray irradiation over the whole energy range from eV to GeV. Our studies on the ion induced conversion of ices include an examination of the linear energy transfer due to stopping processes, by which the input projectile loses its original energy to particles in the target. This deposited energy rate has been calculated for various species and for different cosmic ray spectra inside and outside of the heliosphere. The results can be used to predict a radiation induced chemical conversion rate of simple chemical species to complex ones by means of forthcoming experimental data. Baratta,~G A., Leto,~G., and Palumbo,~M E.: A comparison of ion irradiation and UV photolysis of $\chemCH_4$ and $\chemCH_3OH$, Astron. Astrophys., 384, 343–349, 2002. Cooper,~J F., Christian,~E R., Richardson,~J D., and Chi~Wang: Proton irradiation of Centaur, Kuiper Belt, and Oort cloud objects at plasma to cosmic ray energy, Earth, Moon and Planets, 92, 261–277, 2003. Fahr,~H., Fichtner,~H., Scherer,~K., and Stawicki,~O.: Variable terrestrial particle environments during the galactic orbit of the Sun, in: Astrophysics and Space Science Library, edited by Frisch, P., 338, 259–279, Springer, 2006. Gerakines,~P A., Moore,~M., and Hudson,~R.: Energetic processing of laboratory ice analogs: UV photolysis versus ion bombardment, J. Geophys. Res., 106, 33 381–33 385, 2001. Hudson,~R L. and Moore,~M H.: Radiation chemical alterations in solar system ices: An overview, J. Geophys. Res., 106, 33 275–33 284, 2001. Ivanov,~V S.: Radiation chemistry of polymers, Leiden, 1992.\vadjust Kaiser,~R I. and Roessler,~K.: Theoretical and laboratory studies on the interaction of cosmic-ray particles with interstellar ices, III. Suprathermal chemistry induced formation of hydrocarbon molecules in solid methane ($\chemCH_4$), ethylene and acetylene $(\chemC_2H_4), (\chemC_2H_2)$, Astrophys. J., 503, 959–975, 1998. Luu,~J X. and Jewitt,~D C.: KUIPER BELT OBJECTS: Relics from the Accretion Disk of the Sun, Ann. Rev. Astron. Astrophys., 40, 63–101, 2002. McCall,~B J., Huneycutt,~R J. Saykally,~T R., et al.: An enhanced cosmic-ray flux towards ζ Persei inferred from a laboratory study of the $\chemH_3^+ - \cheme^-$ recombination rate, Nature, 422, 500–503, 2003. Trujillo,~C A. and Brown,~M E.: A correlation between inclination and color in the classical Kuiper Belt, Astrophys. J., 566, L125–L128, 2002. Yeghikyan,~A G., Viti,~S., and Williams,~D A.: The formation of heavy hydrocarbons in molecular clouds, Mon. Not. R. A. S., 326, 313–316, 2001. Ziegler,~J F., Biersack,~J P., and Littmark,~U.: The stopping and range of ions in solids, Pergamon Press, NY, 2003.