Analysis of Dust Production in Planetary Rings and Investigation of the Delivery of Water to the Terrestrial Planets During Planet Formation

Abstract

In this thesis, we discuss about two main different subjects. In the first part, we discuss Saturn’s G-ring arc, while in the second part about water delivery to the terrestrial planets during the growth of Jupiter and Saturn. Here starts part I. Arcs within planetary rings are densely populated regions, believed to form through collisions between interplanetary particles and a satellite embedded within the arc. These collisions can disintegrate material from the satellite, generating dust and smaller bodies. Fragment collisions further contribute to dust production and the formation of larger bodies within the arc. Previous studies have revealed that these arcs primarily consist of micrometer-sized particles. However, these particles face challenges due to perturbative forces, diminishing their lifespan and removing them from the arc. Estimates indicate that dust particles affected by solar radiation pressure would be expelled from the arc within 40 years, posing a challenge to sustaining the dust material. To address this, we propose a refined model of dust generation, considering collisions between macroscopic bodies present in the arc. Through simulations, we demonstrate that disruptive impacts with these bodies contribute significantly to dust deposition within the arc, potentially prolonging its existence. Our findings suggest that these bodies could continually generate dust material, potentially replenishing and sustaining the arc over time. Here starts the part II. Evidence from Earth’s water D/H ratio suggests that one of the main sources of Earth’s water may have been carbonaceous chondrites’ parent bodies. Our simulations simultaneously model the growth and/or migration of Jupiter and Saturn and the accretion of terrestrial planets. We are particularly interested in investigating the influence of the growth and migration of Jupiter and Saturn on the delivery of water-rich planetesimals into the inner solar system. We explored Jupiter and Saturn formed nearly in situ and migrating planetesimals were distributed into two rings. The so-called “inner ring” was assumed to contain water-poor planetesimals distributed from 0.5 to 1.5 AU. The so-called outer ring contained water rich planetesimals distributed from 5 to 20 AU. Planetary embryos in the inner ring start with their masses between those of the Moon and Mars. Our simulations were integrated using a modified version of the Symba integrator for 100 million years. Our results indicate that the growth and migration of Jupiter and Saturn can deliver about 0.1-1% of water-rich material originally from the outer ring into the terrestrial region, depending on model-assumed parameters. S-type asteroids observed in the belt are traditionally associated with planetesimals from the inner ring. C-type asteroids in the belt are thought to sample planetesimals from the giant planet region. Our simulations where Jupiter and Saturn formed nearly in situ can naturally deliver water to Earth and explain the currently observed fractions between C and S-type asteroids in the belt. On the other hand, the simulations, where Jupiter and Saturn migrated from distant regions, deliver all of Earth’s water but tend to implant relatively larger fractions of water-rich planetesimals into the belt than the observed ones, making this scenario potentially inconsistent with the current asteroid belt.