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Orbital and collisional dynamics of small bodies
Rozehnal, Jakub ; Brož, Miroslav (advisor) ; Granvik, Mikael (referee) ; Delbo, Marco (referee)
This work is devoted to a study of dynamical and collisional processes, governing populations of small bodies in the Solar System. It pays special attention to asteroid families and Jupiter Trojans. Librating around L4 and L5 Lagrangian points of the Sun-Jupiter-asteroid system, these asteroids are believed to be captured from the trans- Neptunian region during a giant planet system instability about 4 Gy ago. We discovered (back in 2011) there is only one significant collisional family among Trojans, associated with C-type asteroid (3548) Eurybates, i.e., one of the targets for the upcoming 'Lucy' mission. Detailed analysis of new proper resonant orbital elements, colours and albedos, together with statistical significance computations, allowed us to find five more collisional families: Hektor, (9799), Arkesilaos, Ennomos, and (247341). The discovery of the first D-type family associated with (624) Hektor was the most surprising, because it is the most primitive taxonomic type. Using long-term dynamical simulations of synthetic families, evolving by chaotic diffusion, we estimated the ages of the Eurybates and Hektor families, approximately (2.5±1.5) Gy for both. We also studied impact processes by means of the smoothed-particle hydrodynamics (SPH). We simulated cratering events on (624) Hektor, the origin...
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Asteroid families and their relation to planetary migration
Rozehnal, Jakub ; Brož, Miroslav (advisor) ; Vokrouhlický, David (referee)
In this thesis, we study how the planetary migration affects asteroid families. We identify the families among the Trojans of Jupiter by analysing their properties in the space of resonant elements, the size-frequency distribution and the colour indices. The previously reported number of families (10) seems to be overestimated, our analysis indicates that there is only one collisional family among Trojans with the parent-body size DPB > 100 km. We also performed a simulation of the long-term orbital evolution of the Trojan families. We used a modified version of the SWIFT symplectic integrator where the migration is set analytically. We found that the families are unstable even in the late stages of the migration, when Jupiter and Saturn recede from their mutual 1:2 resonance. Hence, the families observed today must have been created after the planetary migration ended. In the last part of the work, we study a formation of asteroid families in the Main Belt during the Late Heavy Bombardement. We simulate perturbations induced by migrating planets in the "jumping Jupiter" scenario (Morbidelli et al., 2010) and we conclude that big families (DPB > 200 km) created during the bombardement should be observable today.
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