  We present results of the analysis of cometary X-ray spectra with an extended
version of our charge exchange emission model (Bodewits et al. 2006). We have
applied this model to the sample of 8 comets thus far observed with the Chandra
X-ray observatory and ACIS spectrometer in the 300-1000 eV range. The surveyed
comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), C/2000 WM1
(LINEAR), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), C/2001 Q4 (NEAT), 9P/2005
(Tempel 1) and 73P/2006-B (Schwassmann-Wachmann 3) and the observations include
a broad variety of comets, solar wind environments and observational
conditions. The interaction model is based on state selective, velocity
dependent charge exchange cross sections and is used to explore how cometary
X-ray emission depend on cometary, observational and solar wind
characteristics. It is further demonstrated that cometary X-ray spectra mainly
reflect the state of the local solar wind. The current sample of Chandra
observations was fit using the constrains of the charge exchange model, and
relative solar wind abundances were derived from the X-ray spectra. Our
analysis showed that spectral differences can be ascribed to different solar
wind states, as such identifying comets interacting with (I) fast, cold wind,
(II), slow, warm wind and (III) disturbed, fast, hot winds associated with
interplanetary coronal mass ejections. We furthermore predict the existence of
a fourth spectral class, associated with the cool, fast high latitude wind.
