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Interactions of migrating giant planets and small solar-system bodies
Chrenko, Ondřej ; Brož, Miroslav (advisor)
Changes of semimajor axes of giant planets, which took place 4 billion years ago and evolved the Solar System towards its present state, affected various populations of minor Solar-System bodies. One of these populations was a group of dynamically stable asteroids in the 2:1 mean-motion resonance with Jupiter which reside in two islands of the phase space, denoted A and B, and exhibit lifetimes comparable to the age of the Solar System. The origin of stable asteroids has not been explained so far. Our main goal is to create a viable hypothesis of their origin. We update the resonant population and its physical properties on the basis of up-to-date observational data. Using an N-body model with seven giant planets and the Yarkovsky effect included, we demonstrate that the depletion of island A is faster compared to island B. We then investigate: (i) survivability of primordial resonant asteroids and (ii) capture of the population during planetary migration, using a recently described scenario with an escaping fifth giant planet and a jumping-Jupiter instability. We employ simulations with prescribed migration, smooth late migration and we statistically evaluate the results using dynamical maps. We also model collisions during the last 4 billion years. We conclude that the long-lived group was created by a...
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Early phases of formation and evolution of planetary systems
Chrenko, Ondřej ; Brož, Miroslav (advisor) ; Kley, Wilhelm (referee) ; Morbidelli, Alessandro (referee)
We study orbital evolution of multiple Earth-mass protoplanets in their natal protoplanetary disk. Our aim is to explore the interplay between migration of protoplanets driven by the disk gravity, their growth by pebble accretion, and accretion heating which affects gas in their neighbourhood. Radiation hydrodynamic (RHD) simulations in 2D and 3D are used to model the problem. We find that the heating torque, i.e. the torque exerted by asymmetric hot underdense gas near accreting protoplanets, significantly changes the migration. Specifically, it excites orbital eccentricities of migrating protoplanets, thus preventing their capture in chains of mean-motion resonances. The protoplanets then undergo numerous close encounters and form giant planet cores by mutual collisions. Additionally, if inclinations also become excited, we describe a new mechanism that can form binary planets by means of consecutive two-body and three-body encounters, with the assistance of the disk gravity. Finally, our 3D RHD simulations reveal a complex distortion of the gas flow near an accreting protoplanet, driven by baroclinic perturbations and convection. For specific temperature-dependent opacities of the disk, an instability is triggered which redistributes gas around the protoplanet and leads to an oscillatory migration,...
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Interactions of migrating giant planets and small solar-system bodies
Chrenko, Ondřej ; Brož, Miroslav (advisor)
Changes of semimajor axes of giant planets, which took place 4 billion years ago and evolved the Solar System towards its present state, affected various populations of minor Solar-System bodies. One of these populations was a group of dynamically stable asteroids in the 2:1 mean-motion resonance with Jupiter which reside in two islands of the phase space, denoted A and B, and exhibit lifetimes comparable to the age of the Solar System. The origin of stable asteroids has not been explained so far. Our main goal is to create a viable hypothesis of their origin. We update the resonant population and its physical properties on the basis of up-to-date observational data. Using an N-body model with seven giant planets and the Yarkovsky effect included, we demonstrate that the depletion of island A is faster compared to island B. We then investigate: (i) survivability of primordial resonant asteroids and (ii) capture of the population during planetary migration, using a recently described scenario with an escaping fifth giant planet and a jumping-Jupiter instability. We employ simulations with prescribed migration, smooth late migration and we statistically evaluate the results using dynamical maps. We also model collisions during the last 4 billion years. We conclude that the long-lived group was created by a...
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Interactions of migrating giant planets and small solar-system bodies
Chrenko, Ondřej ; Brož, Miroslav (advisor) ; Wünsch, Richard (referee)
Changes of semimajor axes of giant planets, which took place 4 billion years ago and evolved the Solar System towards its present state, affected various populations of minor Solar-System bodies. One of these populations was a group of dynamically stable asteroids in the 2:1 mean-motion resonance with Jupiter which reside in two islands of the phase space, denoted A and B, and exhibit lifetimes comparable to the age of the Solar System. The origin of stable asteroids has not been explained so far. Our main goal is to create a viable hypothesis of their origin. We update the resonant population and its physical properties on the basis of up-to-date observational data. Using an N-body model with seven giant planets and the Yarkovsky effect included, we demonstrate that the depletion of island A is faster compared to island B. We then investigate: (i) survivability of primordial resonant asteroids and (ii) capture of the population during planetary migration, using a recently described scenario with an escaping fifth giant planet and a jumping-Jupiter instability. We employ simulations with prescribed migration, smooth late migration and we statistically evaluate the results using dynamical maps. We also model collisions during the last 4 billion years. We conclude that the long-lived group was created by a...
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Origin of asteroids in the 2:1 mean-motion resonance with Jupiter
Chrenko, Ondřej ; Brož, Miroslav (advisor) ; Hanuš, Josef (referee)
Asteroids located in the 2:1 mean-motion resonance with Jupiter are classified as stable (called Zhongguos), marginally stable (called Griquas) and unstable (called Zulus) according to their dynamical lifetime. The stable asteroids reside in two separate stable islands in the pseudo-proper element space. In this thesis, we update the resonant population on the basis of up-to-date observational data and we determine orbital and physical properties of the resonant population. Using collisional models, we demonstrate that the observed Zhongguos and Griquas might be up to 4 Gyr old, thus their origin might be related to the planetary migration. Performing dynamical N-body simulations, we test two hypotheses of the origin of the long-lived population: the primordial population scenario, and the asteroidal capture scenario. Our results imply that the resonant population is not primordial but it was rather formed by the asteroids captured from an asteroidal family located in outer main belt.
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