Formation of the Earth and Moon: Influence of Small Bodies

Abstract

The paper discusses a model of the bombardment of the Earth and the Moon by small bodies when these planets were formed. It is shown that the total ice mass delivered with the bodies to the Earth from the feeding zone of the giant planets and the outer asteroid belt could have been comparable to the total mass of the Earth's oceans. Objects that initially crossed Jupiter's orbit could become Earth-crossers mainly within the first one million years. Most collisions of bodies originally located at a distance of 4 to 5 AU (astronomical units) from the Sun with the Earth occurred during the first ten million years. Some bodies from the Uranus and Neptune zones could fall onto the Earth in more than 20 million years. From their initial distances from the Sun of about 3 to 3.5 AU, some bodies could fall onto the Earth and Moon in a few billion years for the model that takes into account only the gravitational influence of the planets. The ratio of the number of bodies that collided with the Earth to the number of bodies that collided with the Moon varied mainly from 20 to 40 for planetesimals from the feeding zone of the terrestrial planets. For bodies originally located at a distance of more than 3 AU from the Sun, this ratio was mainly in the range between 16.4 and 17.4. The characteristic velocities of collisions of planetesimals from the feeding zones of the terrestrial planets with the Moon varied from 8 to 16 km/s, depending on the initial values of the semi-major axes and eccentricities of orbits of the planetesimals. The collision velocities of bodies that came from the feeding zones of Jupiter and Saturn with the Moon were mainly from 20 to 23 km/s.

arXiv comment8 pages

References in corpus (28)

• Rapid planetesimal formation in turbulent circumstellar discs
• Building Terrestrial Planets
• Making other Earths: Dynamical Simulations of Terrestrial Planet Formation and Water Delivery
• Particle Clumping and Planetesimal Formation Depend Strongly on Metallicity
• Zonal Flows and Long-Lived Axisymmetric Pressure Bumps in Magnetorotational Turbulence
• Towards planetesimals: dense chondrule clumps in the protoplanetary nebula
• Orbital Evolution of Planets Embedded in a Planetesimal Disk
• Water Delivery and Giant Impacts in the 'Grand Tack' Scenario
• Formation of Kuiper Belt Binaries by Gravitational Collapse
• On the Formation of Planetesimals via Secular Gravitational Instabilities with Turbulent Stirring
• Planet formation bursts at the borders of the dead zone in 2D numerical simulations of circumstellar disks
• Adding particle collisions to the formation of asteroids and Kuiper belt objects via streaming instabilities
• Towards Initial Mass Functions for Asteroids and Kuiper Belt Objects
• High-resolution simulations of planetesimal formation in turbulent protoplanetary discs
• Multiple Impact Origin for the Moon
• Tidal evolution of the Moon from a high-obliquity, high-angular-momentum Earth
• Embryos grown in the dead zone: Assembling the first protoplanetary cores in low mass self-gravitating circumstellar disks of gas and solids
• Modeling the Historical Flux of Planetary Impactors
• From Disks to Planets
• Comet and Asteroid Hazard to the Terrestrial Planets
• Migration of Small Bodies and Dust to Near-Earth Space
• Comet Hazard to the Earth
• Probabilities of collisions of planetesimals from different regions of the feeding zone of the terrestrial planets with the forming planets and the Moon
• Formation of trans-Neptunian satellite systems at the stage of condensations
• Formation of embryos of the Earth and the Moon from the common rarefied condensation and their subsequent growth
• Collision probabilities of migrating small bodies and dust particles with planets
• Origin of the Moon
• Migration of Comets to the Terrestrial Planets

Cited by in corpus (4)

• Migration processes in the Solar System and their role in the evolution of the Earth and planets
• Growth of the Moon due to bodies ejected from the Earth
• Probabilities of collisions of bodies ejected from forming Earth with the terrestrial planets
• Migration of celestial bodies in the Solar system and in several exoplanetary systems