Luminosity of the bolides created by SL-9 comet fragments in the Jovian atmosphere

Abstract

2D and 3D radiation hydrodynamic simulations of the bolide stage of the SL-9 comet fragments impact onto Jupiter have been fulfilled taking into account radiation driven ablation. Detailed tables of spectral opacities of hot Jovian atmosphere and of ablation products have been calculated and used in the simulations. It has been shown that methane and its products substantially change opacities of hot Jovian atmosphere in comparison to zero-metallicity opacities of pure helium-hidrogen mixture. Composition of the SL-9 comet in the model has been varied from pure water to pure chondritic dust, including volatile/dust ratio estimated for comet Halley. We find that a dense cloud of vapor formed at altitudes of about 150–300 km moves with fragments to an altitude of the 1 bar level and substantionally (by a factor of two-three) increases the size of the emitting volume and intensity of radiation. Radiation fluxes in each waveband of Galileo mission instruments (SSI, PPR, NIMS and UVS) have been calculated in the direction of Galileo for various sizes of the SL-9 fragments. Sizes of some of the fragments have been determined from comparision of theoretical intensities with observations, namely 0.3 – 0.8 km.