Planetary bombardment in the first billion years of the solar system

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K17662
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Brasser Ramon 東京工業大学, 地球生命研究所, 特任准教授 (30747142)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: planetary bombardment

Outline of Final Research Achievements

We have calculated the intensity of bombardment onto the terrestrial planets within the first 1 Gyr of the formation and evolution of the solar system. We employed a combination of dynamical N-body simulations of terrestrial planet formation, their subsequent dynamical evolution and Monte Carlo impact simulations. We constrained the intensity of the bombardment against the abundance of highly-siderophile elements in the mantles of Earth and Mars, and isotopic variations in martian materials. We conclude that there was no late heavy bombardment at 4.1 Ga or 3.95 Ga, the bombardment was a monotonic decline from 4.4 Ga onwards and that the Earth was conducive to forming a biosphere from 4.4 Ga onwards. We further conclude that Mars formed far from the Sun, in the asteroid belt, which places severe limitations on the evolution of the early Solar System.

Free Research Field

Planetary science