Implications of the Galilean satellites ice envelope explosions II. The origin of the irregular satellites

The problem of the origin of the irregular satellites is solved readily in the context of a hypothesis involving explosion of the massive ice envelopes of the Galilean satellites saturated by electrolysis products. The thrown-off unexploded (primary) ice fragments of the outermost cold layers of the envelopes are also saturated by electrolysis products. In the course of explosive ejection their internal energy increases due to shock wave heating, as a result of which they will be able to detonate in subsequent sufficiently energetic collisions. The secondary fragments from new explosions may acquire additional velocity up to a few km s^–1 without breakup into small pieces.Gravitational perturbations by the parent satellites can eject the primary fragments moving near their orbits into the periphery of or beyond Jupiter's sphere of action. If such a fragment explodes in the outer zone of the sphere, then secondary fragments may become irregular satellites resulting in the so-called internal capture (the possibilities of capture considered earlier involved only bodies entering the sphere of action from outside).The mass of the primary fragment responsible for the inner (direct) group of Jupiter's irregular satellites is estimated as 10¹⁹ kg, and the additional velocity acquired by secondary fragments as 1.3 km s^–1; evaluation of the mass of the fragment responsible for the outer (retrograde) group yields 10¹⁸ kg, and that of the additional velocity of secondary fragments, 2 km s^–1.The ice envelopes of the Galilean and similar moonlike satellites should contain impurities corresponding to the composition of type C1 carbonaceous chondrites; therefore after sublimation of water ice the irregular satellites (just as type C asteroids, the Trojans and comets) exhibit spectro-photometric properties similar to those of C-type objects.