Some Aspects of the Formation of the Solar System

Initial Evolution of the Moon

“…The results of the numerical solution of the problem for the 3D model of the environment [16,17] are obtained, which allow us to trace the formation and further dynamics of three-dimensional anomalous in temperature and composition areas resulting from the fall of bodies and particles on the surface of a growing planet when they are randomly distributed over masses. Quantitative estimates of the parameters that determine the solution of the problem are extremely difficult.…”

“…The model [21] on the formation of planets and their satellites from a protoplanetary cloud is used as the initial one. The results of numerical modeling obtained by us [16,17] showed that already at an early stage of the Earth's accumulation process, heat release during decay by short-lived naturally radioactive elements and above all 26 Al is enough to exceed in the protoplanetary dimensions (50-100 km); a molten central region and a relatively thin, solid, predominantly silicate upper envelope could be formed. This creates the conditions for the mechanism of differentiation of a substance into a chemical reservoir of the future predominantly iron core and a silicate reservoir of the Earth's mantle to be realized at small relative velocities of collisions of small bodies-pre-planets.…”

“…The mathematical description of mass-energy transport in a growing selfgravitating body of variable radius consists in setting boundary value problems for a system of equations for the balance of momentum, energy, conservation of mass of matter, and the Stefan problem at the boundaries of regions with melt zones [16][17][18]:…”

“…We were faced with the task: using the model of accumulation of the terrestrial planets proposed in papers [16][17][18], to conduct numerical simulations of the temperature distribution in the interior of the planet for successively increasing with time values of the body radius in the 3D environment and in contrast to the results [18], explore the features of the evolution of primary heterogeneities depending on the rate of accumulation of the second largest body in the "feeding" zone of a growing Earth in a 3D process model. In works [16][17][18], the proposed model of the heterogeneous accumulation of the Earth, based on a two-stage mechanism for the formation of the pre-planetary of the planet, is presented. It assumes that in the first stage, primary pre-planets are formed, the central part of which consists of the most high-temperature condensates close in composition to the CAI-Ca-Al inclusions found in the Allende meteorite.…”

“…The ratio of 26 Al/ 27 Al in protoplanetary matter is estimated to be 5 Â 10 À5 [20]. With this content of 26 Al, as the mass of the pre-planetary grows, the temperature of their central regions increases, and in the center of the pre-planetary with a radius of more than 200 km, it can reach 2200 K [17]. This is quite enough to melt the Ca-Al material in the central part of the core, the melting point of which is 1830 K [1], and the iron-nickel mixture in its middle envelope.…”