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Re Vision
Švehla, Jakub ; Šrámek, Jan (referee) ; Kögler, Žaneta (advisor)
In form of 3D animation the thesis depicts the steps of mankind towards the expansion of civilization beyond planet Earth. Chronologically it exposes essential moments of technological development (in major) preceding the journey for the distant planets. Images of today's state of civilization are combined with constructions of former theoretical concepts and with fully fictitious elements to form visuals illustrating the roadmap to extraterrestrial expansion.
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Predictive software for Earth collision with Near Eartch Objects
Stopka, Jiří ; Daněk, Vladimír (referee) ; Bartoněk, Jaroslav (advisor)
Aim of this bachelor’s thesis is to research and discuss the basics of orbital mechanics and their application on a real problem. The application of orbital mechanics is made by creating a software for predicting Earth’s collision with Near-Earth Objects in Borland Delphi 7 development enviroment. The created software should be able to predict close approaches of Earth and Near-Earth Objects in a time scale selected by user and issue a warning in case of a dangerous close approach.
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Identification methods of genetically related asteroids
Fatka, Petr ; Pravec, Petr (advisor) ; Christou, Apostolos (referee) ; Novakovič, Bojan (referee)
In this thesis, I describe the main ideas and summarize the results of four refereed papers I contributed to (three times as the second author and once as the first author). The first step of each of these papers was the identification of genetically related asteroid and their membership confirmation. Since members of asteroid pairs and clusters have a very similar heliocentric orbits, we employed and further developed methods based on backward orbital integrations. The chronologically first paper Pravec et al. (2018) deals with asteroid clusters and their similarity to asteroid pairs. The second paper Pravec et al. (2019) is a complex study of 93 asteroid pairs with many interesting results, such as the existence of binary asteroids among asteroid pairs. The third paper Moskovitz et al. (2019) deals with an identification of asteroid pairs in the near-Earth population and a detail study of two probable asteroid pairs. The fourth paper, Fatka et al. (2020), studies the phenomenon of cascade disruption in asteroid clusters, which results in multiple generations (with different ages) of escaped secondaries in some asteroid clusters.
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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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Inner belt asteroids in the spin-orbital resonance
Vraštil, Jan ; Vokrouhlický, David (advisor)
Context: Slivan (2002) determined spin state of ten asteroids in the Koronis family. Surprisingly, all four asteroids with prograde sense of rotation were shown to have spin axes nearly parallel in the inertial space. All asteroids with retrograde sense of rotation had large obliquities and rotation periods either short or long. It was shown that Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect can explain all these peculiar facts. In particular, it drives spin axes of the prograde rotators to be captured in a secular spin-orbital resonance known as Cassini state 2. Vokrouhlický et al. (2002) dubbed these configurations "Slivan states". Aims: A question arises whether Slivan states could exist also in other regions of the main asteroid belt, in particular its inner part, where observations are most easily obtained. Here, however, dynamical difficulties arise due to convergence of the proper frequency s and the planetary frequency s6. We investigate possibilities of a long-term stable capture in the Slivan state in the inner part of the main belt. Method: We used SWIFT integrator to determine orbital evolution of selected asteroids in the inner part of the main belt. In the case of 20 Massalia, we observed the asteroid in 2011, and used these new data to help better solve the rotation state using the...
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Predictive software for Earth collision with Near Eartch Objects
Stopka, Jiří ; Daněk, Vladimír (referee) ; Bartoněk, Jaroslav (advisor)
Aim of this bachelor’s thesis is to research and discuss the basics of orbital mechanics and their application on a real problem. The application of orbital mechanics is made by creating a software for predicting Earth’s collision with Near-Earth Objects in Borland Delphi 7 development enviroment. The created software should be able to predict close approaches of Earth and Near-Earth Objects in a time scale selected by user and issue a warning in case of a dangerous close approach.
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Identification methods of genetically related asteroids
Fatka, Petr ; Pravec, Petr (advisor) ; Christou, Apostolos (referee) ; Novakovič, Bojan (referee)
In this thesis, I describe the main ideas and summarize the results of four refereed papers I contributed to (three times as the second author and once as the first author). The first step of each of these papers was the identification of genetically related asteroid and their membership confirmation. Since members of asteroid pairs and clusters have a very similar heliocentric orbits, we employed and further developed methods based on backward orbital integrations. The chronologically first paper Pravec et al. (2018) deals with asteroid clusters and their similarity to asteroid pairs. The second paper Pravec et al. (2019) is a complex study of 93 asteroid pairs with many interesting results, such as the existence of binary asteroids among asteroid pairs. The third paper Moskovitz et al. (2019) deals with an identification of asteroid pairs in the near-Earth population and a detail study of two probable asteroid pairs. The fourth paper, Fatka et al. (2020), studies the phenomenon of cascade disruption in asteroid clusters, which results in multiple generations (with different ages) of escaped secondaries in some asteroid clusters.
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Inner belt asteroids in the spin-orbital resonance
Vraštil, Jan ; Vokrouhlický, David (advisor)
Context: Slivan (2002) determined spin state of ten asteroids in the Koronis family. Surprisingly, all four asteroids with prograde sense of rotation were shown to have spin axes nearly parallel in the inertial space. All asteroids with retrograde sense of rotation had large obliquities and rotation periods either short or long. It was shown that Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect can explain all these peculiar facts. In particular, it drives spin axes of the prograde rotators to be captured in a secular spin-orbital resonance known as Cassini state 2. Vokrouhlický et al. (2002) dubbed these configurations "Slivan states". Aims: A question arises whether Slivan states could exist also in other regions of the main asteroid belt, in particular its inner part, where observations are most easily obtained. Here, however, dynamical difficulties arise due to convergence of the proper frequency s and the planetary frequency s6. We investigate possibilities of a long-term stable capture in the Slivan state in the inner part of the main belt. Method: We used SWIFT integrator to determine orbital evolution of selected asteroids in the inner part of the main belt. In the case of 20 Massalia, we observed the asteroid in 2011, and used these new data to help better solve the rotation state using the...
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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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Distribution functions of asteroid physical properties
Cibulková, Helena ; Ďurech, Josef (advisor) ; Marciniak, Anna (referee) ; Polishook, David (referee)
Title: Distribution functions of asteroid physical properties Author: Helena Cibulková Institute: Astronomical Institute of Charles University Supervisor: Mgr. Josef Ďurech, Ph.D., Astronomical Institute of Charles Univer- sity Abstract: In this thesis, I utilize photometric data sparse in time produced by all-sky surveys and investigate physical properties of large asteroid populations. In principle, the individual approach to asteroid modeling cannot compass all objects because new asteroids are continually discovered and we do not have enough data for them. Therefore, in this work I present an essentially different, statistical approach. In a series of papers, we developed two independent methods which use a triaxial-ellipsoid approximation, and we test their applicability and limits. We prove they can be used to the photometric databases like Lowell Observatory database or Pan-STARRS. The output quantities are distributions of the spin axis directions and shape elongations for asteroid populations, and using the Kolmogorov-Smirnov test we search for differences among them. The main result of my work is that the distribution of ecliptical longitudes of spin axes is nonuniform. Moreover, this nonuniformity is more significant for asteroids with low orbital inclinations and the distribution is dependent on...
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