The calculated High Resolution Imager count rate of 4.4 per second and the spatial distribution of the x-ray emission agree with the observations. Cometary x-rays present a new and sensitive tool to monitor cometary activity and solar wind ion composition. Plasma flow field in the coma of Hyakutake on 27 March 1996, as computed by the 3D MHD model. Solar wind streamlines originating from the Sun, which is to the left in the figure, are shown as white and purple lines. The yellow line shows the location of the bowshock.
Color code gives logarithm of plasma mass density, increasing from blue to red.
In both images, the x-ray emission shows a crescent shape and the maximum of the emission is displaced Sunward from the nucleus. The scale of both images is the same. The computed results have been scaled to the same integrated brightness as the measurements from 27.8 March 1996. The direction of the sun in noted by the arrow. We note that the spectrum is fairly universal and it is expected to change only moderately from comet to comet.