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Extensions of the main belt collisional model
Vávra, Michael ; Brož, Miroslav (advisor) ; Scheirich, Petr (referee)
The Main Belt, the region between the orbits of Mars and Jupiter, is the home to more than 1 million asteroids. These asteroids form orbital groups, i.e., asteroid families formed by collisions; and also spectral groups (taxonomies) with different chemical composition, in particular, carbonaceous (C-types) and silicate (S-types). In this thesis, we extend the existing collisional model by finding appropriate dependence of the strength vs. size (also known as the scaling law) for these two groups. We used color indices and geometric albedos of 56 and 72 spectroscopically confirmed C- and S-types (control samples) and statistical methods on 1 065 054 asteroids, to assign C-, S- or other-types (neither C- nor S-type). This allowed us to construct the observed size-frequency distributions (SFDs) for several sub-populations constrained either in the semi-major axis (inner, middle, outer) or taxonomy (C, S, other). Then we used the Monte-Carlo code Boulder (Morbidelli et al. 2009). to compute the long-term collisional evolution (4.5 billion years) and derive synthetic SFDs. We find that the scaling laws for C- and S-types disagree with the ones proposed by Holsapple & Housen (2019). Our best-fit scaling laws indicate that S-types must be weakened below approximately 1 km compared to C-types, to explain a...
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Asteroids@home - using distributed computing for asteroid lightcurve inversion
Vávra, Michael ; Ďurech, Josef (advisor) ; Scheirich, Petr (referee)
Distributed computing is a great helper in many fields of human activity. Distributed computing is not only helper, but also a tool, which can finish many computations in less time. Modelling of the asteroids, findings coordinates of their poles or derivations of their rotational periods are all very time consuming processes, which can all be done faster with the usage of the distributed computing. In order to execute these processes, we have to parallelize these processes, which means we have to split computations of these processes into many computers. Here comes a project Asteroids@home, which can on the one hand execute these processes and on the other hand the project can parallelize these processes. Due to this we know shapes, coordinates of poles and periods of many asteroids these days. However, periods of the asteroids are not always correct and therefore it is necessary to study them more further and decide if they are correct or not. 1
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