Physical properties of the aerosol debris generated by the impact of fragment H of comet P/Shoemaker‐Levy 9 on Jupiter

The physical properties of the aerosol debris coming from the impact of fragment H of comet P/Shoemaker‐Levy on Jupiter are analyzed. Based on a high spatial resolution image set obtained at the 4.2m William Herschel Telescope at La Palma (Spain), we derived detailed limb darkening curves at three wavelengths (3600, 8920 and 9480 Å), which we used to retrieve the aerosol physical properties and spatial distribution in the central core region of the impact site. We derived these properties combining the observations at two dates, that corresponding to the night of July 18th, 1994, just after the impact time, and that of July 21st, 1994. Radiative transfer models in combination with a Mie scattering program were used to retrieve the possible values of aerosol properties and spatial distribution compatible with these observations. The main results of the model computations are that the particles are rather dark, with imaginary refractive indexes varying between 0.02 at 3600 Å and 0.006 in the 9000 Å region, have a mean radius of about 0.15 µm, and are distributed between 1 and 450 mbar with a total column concentration of 8.2 × 109 cm−2, giving a total optical thickness of 3.6 at 9480 Å. A lower limit to the volume of the impact debris aerosol is estimated to be that corresponding to a sphere of about 230 m in diameter.