SPATIAL DIFFERENCES IN THE VISIBLE NEAR INFRARED CONTINUUM EMISSION OF COMET C/1995 O1 (HALE-BOPP)/

Imaging spectroscopy data in the 0.4-1 mu m spectral region of comet H ale-Bopp have been analysed in order to study the spatial distribution and physical properties of the dust grains in the coma. The data pres ented cover a period of three days close to perihelion. The spectra ha ve been processed by means of the principal component analysis in orde r to individuate coherent spatial units with different spectral proper ties. The study shows the presence of two regions on the sunward and a ntisunward sides of the nucleus exhibiting different continuum emissio ns. This fact is interpreted as due to the presence of dust grains of diverse compositions and/or sizes. In the latter hypothesis, the obser vations could be explained by size sorting due to solar radiation pres sure.