Cometary X-ray emission: Theoretical cross sections following charge exchange by multiply charged ions of astrophysical interest

Abstract

The classical trajectory Monte Carlo (CTMC) method is used to calculate emission cross sections following charge exchange collisions involving highly charged ions of astrophysical interest and typical cometary targets. Comparison is made to experimental data obtained on the EBIT machine at Lawrence Livermore National Laboratory (LLNL) for O8+ projectiles impinging on different targets at a collision energy of 10 eV/amu. The theoretical cross sections are used together with ion abundances measured by the Advanced Composition Explorer as well as those obtained by a fitting procedure using laboratory emission cross sections to reproduce the X-ray spectrum of comet C/LINEAR S4 measured on 14 July 2001.