Contributors to the solar-wind-induced spectrum of cometary x-rays: S and Ne L x-rays, Fe M x-rays and others
POSTER
Abstract
Cravens explained the presence of well resolved x-ray lines from comets as being due to the transfer of electrons from cometary gases (CO, H$_{2}$O, etc.) to create excited states of highly-charged C and O ions from the solar wind (1).~ However, these x rays, with energies in the 250 to 700 eV range, represent only a small fraction of the x rays observed compared with those found in the 50 - 250 eV range (2). Spectra obtained, using solar wind-type ions such as Ne$^{7+,8+}$, S$^{9+}$ and Fe$^{11+}$ from the JPL ECR ion source, suggest that soft x-ray lines from charge-transfer processes terminating on the n=2, and n=3 levels of solar wind ions may contribute significantly to cometary x-ray spectra in this range. \newline 1. T.E. Cravens, Science 297, 1042 (2002). \newline 2. K. Dennerl, J. Englhauser, Joachim Trumper, Science 277,1625 (1997).
*The research at the University of Connecticut has been sponsored by NASA EPSCoR Grant NCC5-601 and that at JPL/Caltech through agreement with NASA.