ISOCAM spectro-imaging observations of the β-Pictoris dust disk

In this paper, we present ISOCAM spectro-imaging observations of the β-Pictoris dust disk. The observations were performed by scanning the 6-15 μm wavelength range with the Circular Variable Filter of ISOCAM; the smallest ISOCAM pixel field of view, 1.5 arcsec, was used. The disk is spatially resolved; the extension is detected up to about 70 AU from the star and appears asymmetric. The silicate dust feature shows that most of the dust is in amorphous form. Faint peaks around 10 μm and 11 μm suggest that part of the dust is in crystalline form, but only at the level of a few per cent. In that sense, the dust in the β-Pictoris system is quite different from the dust observed in comet Hale-Bopp.