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Beyond the Blue Planet - the Formation and Dynamical Evolution of Habitable Worlds


Elser, S. Beyond the Blue Planet - the Formation and Dynamical Evolution of Habitable Worlds. 2013, University of Zurich, Faculty of Science.

Abstract

This thesis is about different aspects of the formation of terrestrial planets and the evolution of planetary systems. Terrestrial planets are formed in various stages, from the condensation of dust particles to the collisions of protoplanets. Hence, this process spans orders of magnitude in size and lasts millions of years. The final stages of the formation process and the long-term dynamical evolution of planetary systems can be studied in detail with modern N-body simulations. Such simulations provide the basis for better understanding the origin, property and occurrence rate of planets that provide suitable conditions for the emergence and evolution of life. These worlds are called habitable planets. In the first part of this thesis we show that massive moons orbiting terrestrial planets are not rare. The Earth's comparatively massive Moon has played an important role in the development of life on our planet. Thus, it is worth to study how often a Earth-like planet is hosting a massive satellite. In a large set of N-body simulations, in which terrestrial planets are formed, we identify giant impacts that can potentially induce the formation of a large moon. Then, we estimate the long-term evolution of the planet-satellite systems considering subsequent impacts, spin-orbit resonance and tidal evolution. According to our study, 1 in 12 Earth-like planets hosts a Moon-like satellite, a surprisingly high number given the fact that it is not the most optimistic approach. In the second part, we study the sensitivity of the estimation of the bulk composition of terrestrial planets on different models and initial conditions. The elemental abundances in the Earth provide the initial conditions for life and clues to the history and formation of the Solar System. The bulk composition of planets is a result of different processes that take place during their formation, which mix material from different regions in the disk. We model the composition of condensed dust particles with condensation equilibrium calculations and trace the collisional growth and the radial mixing of the grown bodies with N-body simulations.We find that the elemental abundances in terrestrial planets depend strongly on the model that describes the thermodynamical structure of the protoplanetary disk. In general, the composition of the inner Solar System can be reproduced, except from the abundance of highly volatile elements and from the composition of Mercury. In the third and final part, we scratch a slightly different topic and turn to the long-term evolution and dynamical stability of planetary systems. Most of the currently known extrasolar planets are massive Jovian-like planets, since these planets are easier to detect. Actually, theory predicts that low-mass Earth-like planets are much more numerous. Starting from systems containing two or three known planets, we add additional low-mass planets and are interested in their stability. Numerous N-body simulations provide the long-term evolution of the systems. The stability of the orbits of the hypothetical planets as well as their interaction with the known planets indicate on which orbits unknown planets could exist. Finally, we predict the existence of habitable low-mass planets in most of the systems we took into account. According to our results, we expect some of them being detected in the next several years.

Abstract

This thesis is about different aspects of the formation of terrestrial planets and the evolution of planetary systems. Terrestrial planets are formed in various stages, from the condensation of dust particles to the collisions of protoplanets. Hence, this process spans orders of magnitude in size and lasts millions of years. The final stages of the formation process and the long-term dynamical evolution of planetary systems can be studied in detail with modern N-body simulations. Such simulations provide the basis for better understanding the origin, property and occurrence rate of planets that provide suitable conditions for the emergence and evolution of life. These worlds are called habitable planets. In the first part of this thesis we show that massive moons orbiting terrestrial planets are not rare. The Earth's comparatively massive Moon has played an important role in the development of life on our planet. Thus, it is worth to study how often a Earth-like planet is hosting a massive satellite. In a large set of N-body simulations, in which terrestrial planets are formed, we identify giant impacts that can potentially induce the formation of a large moon. Then, we estimate the long-term evolution of the planet-satellite systems considering subsequent impacts, spin-orbit resonance and tidal evolution. According to our study, 1 in 12 Earth-like planets hosts a Moon-like satellite, a surprisingly high number given the fact that it is not the most optimistic approach. In the second part, we study the sensitivity of the estimation of the bulk composition of terrestrial planets on different models and initial conditions. The elemental abundances in the Earth provide the initial conditions for life and clues to the history and formation of the Solar System. The bulk composition of planets is a result of different processes that take place during their formation, which mix material from different regions in the disk. We model the composition of condensed dust particles with condensation equilibrium calculations and trace the collisional growth and the radial mixing of the grown bodies with N-body simulations.We find that the elemental abundances in terrestrial planets depend strongly on the model that describes the thermodynamical structure of the protoplanetary disk. In general, the composition of the inner Solar System can be reproduced, except from the abundance of highly volatile elements and from the composition of Mercury. In the third and final part, we scratch a slightly different topic and turn to the long-term evolution and dynamical stability of planetary systems. Most of the currently known extrasolar planets are massive Jovian-like planets, since these planets are easier to detect. Actually, theory predicts that low-mass Earth-like planets are much more numerous. Starting from systems containing two or three known planets, we add additional low-mass planets and are interested in their stability. Numerous N-body simulations provide the long-term evolution of the systems. The stability of the orbits of the hypothetical planets as well as their interaction with the known planets indicate on which orbits unknown planets could exist. Finally, we predict the existence of habitable low-mass planets in most of the systems we took into account. According to our results, we expect some of them being detected in the next several years.

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Additional indexing

Item Type:Dissertation
Referees:Moore Ben, Lake George
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Language:English
Date:20 June 2013
Deposited On:28 Feb 2014 14:36
Last Modified:08 Dec 2017 04:37
Related URLs:http://www.recherche-portal.ch/zbz/action/display.do?fn=display&vid=ZAD&doc=ebi01_prod010046133 (Library Catalogue)

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