Migration of Bodies to the Earth from Different Distances from the Sun

TL;DR

This study analyzes how bodies migrating from various distances in the solar system impact Earth and other terrestrial planets, estimating collision probabilities and water delivery, with implications for planetary formation and bombardment history.

Contribution

It provides new calculations of collision probabilities and water delivery from different solar system regions, highlighting the outer asteroid belt's role in planetary accumulation.

Findings

Collision probabilities vary with initial semi-major axes.

Water delivery from beyond Jupiter could exceed Earth's oceans.

Outer asteroid belt may be a source of late-heavy bombardment.

Abstract

Migration of bodies under the gravitational influence of almost formed planets was studied, and probabilities of their collisions with the Earth and other terrestrial planets were calculated. Based on the probabilities, several conclusions on the accumulation of the terrestrial planets have been made. The outer layers of the Earth and Venus could accumulate similar planetesimals from different regions of the feeding zone of the terrestrial planets. The probabilities of collisions of bodies during their dynamical lifetimes with the Earth could be up to 0.001-0.01 for some initial semi-major axes between 3.2 and 3.6 AU, whereas such probabilities did not exceed 10^-5 at initial semi-major axes between 12 and 40 AU. The total mass of water delivered to the Earth from beyond Jupiter's orbit could exceed the mass of the Earth's oceans. The zone of the outer asteroid belt could be one of the sources of the late-heavy bombardment. The bodies that came from the zone of Jupiter and Saturn typically collided with the Earth and the Moon with velocities from 23 to 26 km/s and from 20 to 23 km/s, respectively.