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Stellar mass-loss in the dynamics of galaxies
Křížek, Miroslav ; Jungwiert, Bruno (advisor) ; Šolc, Martin (referee)
We present an implementation of the statistical approach to the stars-gas mass exchange cycle into an N-body code. First, we summarize available data on stellar mass-loss and derive the time-dependency of the mass-loss rate of a single stellar population. Since the adopted probabilistic scheme that served as a basis for our implementation was limited to the linear star formation law while observations seem to suggest a non-linearity, we derive the non-linear star formation scheme. Both sides of the mass exchange cycle are then implemented into the code with stellar and gaseous particles and compared with an analytic recipe to test their reliability. In the next step, the comparison of such an extended statistical approach with deterministic scheme is performed for a fully dynamical model. The aim of the comparison is to explore divergence between both models of dierent natures. As an illustration of the code application and sensitivity of the resulting galaxy disk dynamics, several comparisons with varying the key parameters are performed.
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N-body simulations of shell galaxies
Ebrová, Ivana ; Jungwiert, Bruno (advisor) ; Šolc, Martin (referee)
Shell galaxies are ordinary elliptical galaxies that contain a fine structure in the form of concentric arcs with sharp edges in their luminous profile. This work contains a summary of our comprehensive study of the actual research and publications on this remarkable phenomenon, concerning both the observations as well as the numerical simulations. Along with it we present the results of our own simulations that broaden our view of the origin of the shells in a radial merger of a massive elliptical galaxy with a less massive one. We have introduced the dynamical friction into the simulation by semi-analytical means based on the Chandrasekhar formula. The main result is that the dynamical friction together with the gradual disintegration of the secondary galaxy that is also discussed can significantly affect the process of the shell formation and must be taken into consideration in their modelling. It turns out that the time scales on which the merger takes place are rather sensitive to the choice of the parameters. We present an estimate of their magnitude in different cases. The mass loss of the secondary galaxy during the merger mitigates the effect of the dynamical friction but does not make its role negligible.
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Recent asteroid breakups and accretion of interplanetary dust on the Earth
Pokorný, Petr ; Šolc, Martin (referee) ; Vokrouhlický, David (advisor)
The major aim of the thesis is an analysis of an accretion of dust originating from breakup events of Emilkowalski and YC2 asterodial families. Using a numerical integrator we follow orbits of individual dust particles, some of which will result in an impact onto one of the planets in the Solar system. Employing some non-trivial transformation we compare recorded impacts onto the Earth to available dust measurements values acquired in antarctic ice-cores. We also analyse the dynamical e ffects of Poynting-Robertson e ffect and their influence on the dust particles of variable sizes.
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Properties of the Orionid meteors observed in 2006
Vojáček, Vlastimil ; Šolc, Martin (referee) ; Koten, Pavel (advisor)
In the present work we study the Orionid 2006 meteor shower. All results in this work come from double station video observations. We study exceptional activity, caused most probably by particles trapped in resonance motion with Jupiter. We focused on light curves, atmospheric trajectories and orbital elements of meteoroids. We can find here comparison with other years of activity of the Orionid meteor shower and comparison with other annual meteor showers.
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Simulation of the astrolabe of the Prague astronomical clock for PC
Makara, Tomáš ; Šolc, Martin (advisor) ; Brož, Miroslav (referee)
In this work we create a computer simulation of the astrolabe of the Prague astronomical clock. The result of this work will by a didactic instrument which will help users discover and understand the astronomical clock. The task is to create a realistic three-dimensional computer model of the astronomical clock and also to implement all movement of the clock. The application will offer three-dimensional realistic visualization of the astronomical clock, description of the clock's parts, and projection of the celestial sphere on the astronomical dial and information which can be read from the dial. The application will provide a possibility to see animation of the astronomical clock and also to set the clock to an arbitrary time during the year.
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Forbidden Oxygen line emission from the traces of meteors
Habuda, Pavol ; Borovička, Jiří (advisor) ; Šolc, Martin (referee)
The aim of this diploma thesis was to study forbidden green oxygen line emission. It was found out that green line emit mainly in heights 100-110 kilometers, exceptionally below 90 kilometers. Time evolution of green line intensity with respect of heights was investigated in detail. There was suggested theoretical dependency and agreement with observed data was fulfilled. Dependency of integral intensity was investigated as well. Mechanisms of excitation and quenching of green line in emission was proposed in previous studies in 70. of previous century. This work discuss with its results. Efficiency of transformation of kinetic energy of meteoroid to forbidden green line's emission was discussed. The concentrations of atomic oxygen was estimated by several way in heights of green line emission.
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