ИСТИНА

We simulated planetesimals passing through the circumplanetary disks of Jupiter and Saturn and capture of their material into the disks with consideration of combined processes of aerodynamic braking, and ablation of planetesimals in the disk’s gas medium. In the following calculation the planetesimals substance is modeled by comet material. We estimated the maximum size which the planetesimals should have when passing through the disk to keep them inside the disk after losing their mass and velocity due to gas drag and ablation. There is a significant dependence of the amount of material captured by the disk on the ablation coefficients. For ablation factors <0.01 s2km-2, the contribution of ablation to the captured mass can be ignored, however, for planetesimals from cometary material, ablation can supply 20-30% of planetesimals mass in the Ganymede and Callisto feeding area and 10%-20% planetesimals mass in the feeding area of Titan. Simulations of aerodynamic braking, fragmentation, and ablation (a comet substance) integrated processes in the gas medium of the Jupiter and Saturn accretion disks were carried out. To estimate the mass of a substance captured by a disk, a degree-law distribution of bodies by mass was assumed [6, 9]. The following relations were estimated: М *ac=(Mc+Ma) /Mt, М *a=Ma/Mt (fig. 1, fig. 2) and М *a=(Mc+Ma)/Mt [6]. The first ratio characterizes the mass fraction of the substance trapped in the disk as a result of mass capture (Mc) and mass ablation (Ma) from the total mass of the planetesimals (Mt) with radii R < R0 passing through the disk. The second one shows the mass fraction of the substance (M*a) captured in the disk with partial evaporation of the planetesimals crossing the disk. The maximum radius of planetesimals R0 in our calculations was set at 100 m and 1000 m. Thus, there is a significant dependence of the amount of matter captured by the accretion disks in the feeding region of the regular ice satellites of Ganymede, Callisto and Titan on the ablation coefficients. For ablation factors < 0.01 s2km-2, the contribution of ablation to the captured mass (the maximum radius of planetesimals is 100-1000 m) can be ignored, however, for planetesimals from cometary material, ablation can supply ∼ 20-30% planetesimals mass in the feeding region of Ganymede and Callisto and ∼ 10% - 20% planetesimals mass in the feeding region of Titan.