• Felter, T. E.
• Van Breugel, W.
• Baragiola, R. A.
• Loeffler, M. J.
• Bradley, J. P.
• Bajt, S.
• Kucheyev, S. O.
• Graham, G.
• Torres, Diego F.
• Dai, Z. R.
• Dukes, C. A.
• Bringa, E. M.
• Tielens, A. G. G. M.

Abstract

While a significant fraction of silicate dust in stellar winds has a crystalline structure, in the interstellar medium nearly all of it is amorphous. One possible explanation for this observation is the amorphization of crystalline silicates by relatively ``low'' energy, heavy-ion cosmic rays. Here we present the results of multiple laboratory experiments showing that single-crystal synthetic forsterite (Mg<SUB>2</SUB>SiO<SUB>4</SUB>) amorphizes when irradiated by 10 MeV Xe ions at large enough fluences. Using modeling, we extrapolate these results to show that 0.1-5.0 GeV heavy-ion cosmic rays can rapidly (~70 Myr) amorphize crystalline silicate grains ejected by stars into the interstellar medium.

Topics

• impedance spectroscopy
• amorphous
• grain
• experiment