The Earth-Moon system as a typical binary in the Solar System

TL;DR

This paper proposes a formation model for the Earth-Moon system as a typical binary in the Solar System, emphasizing collisions of rarefied condensations and their impact on angular momentum and system characteristics.

Contribution

It introduces a new formation scenario involving collisions of rarefied condensations, explaining the Earth's tilt and the Moon's mass acquisition.

Findings

Minimum parental condensation mass for Earth-Moon system is about 0.02 Earth masses.

The Moon could acquire 4-30% of its mass during solid body accumulation.

Multiple collisions could influence Earth's tilt and system dynamics.

Abstract

Solid embryos of the Earth and the Moon, as well as trans-Neptunian binaries, could form as a result of contraction of the rarefied condensation which was parental for a binary. The angular momentum of the condensation needed for formation of a satellite system could be mainly acquired at the collision of two rarefied condensations at which the parental condensation formed. The minimum value of the mass of the parental condensation for the Earth-Moon system could be about 0.02 of the Earth mass. Besides the main collision, which was followed by formation of the condensation that was a parent for the embryos of the Earth and the Moon, there could be another main collision of the parental condensation with another condensation. The second main collision (or a series of similar collisions) could change the tilt of the Earth. Depending on eccentricities of the planetesimals that collided with the embryos, the Moon could acquire 0.04-0.3 of its mass at the stage of accumulation of solid bodies while the mass of the growing Earth increased by a factor of ten.