In this thesis, we study two different topics: collisional probability between two bodies and dynamics of the sporadic meteoroids in the Solar System. Determination of the collision probabilities in the Solar System is one of the important problems in mod- ern celestial mechanics. Here, we generalize classical theories of the collisions between two bodies by Öpik, Wetherill or Greenberg by including the Kozai-Lidov oscillations, a mechanism that significantly change orbital eccentricity and inclination in the Solar System. Sporadic meteors have been studied for many decades providing a wealthy re- source of data. Here, we build dynamical steady-state models for all known populations observed in the sporadic meteoroid complex based on the latest and most precise data provided by Canadian Meteor Orbit Radar (CMOR). Our models using the latest theo- ries for cometary populations in the Solar System accurately describe observed sporadic background population. Our results are in agreement with observations provided by space probes IRAS and LDEF.

Euclid is a medium class mission designed to study the geometry of dark universe. It will work in the visible and near infrared imaging & spectroscopy for a lifetime of 6 years down to the magnitude of mAB = 24.5 with Visible Imager Instrument (VIS) and mAB = 24 with Near Infrared Spectrometer and Photometer instrument in Y, J & H broadband filters. The current survey design will avoid ecliptic latitudes below 15 degrees, but the observation pattern in repeated sequences of four blocks with four broad-band filter seems well-adapted to Solar System object detection. The aim of this thesis is to simulate the Solar System Objects (SSOs) for Near Infrared Spectrometer and Photometer (NISP) instrument and measure the flux/magnitude & position of these moving objects. The simulation of Solar System Objects is implemented in with simulator Imagem using the sky position, velocity, direction of movement and magnitude with respect to band of the objects. The length of the trail is determined using exposure time and after that the sky position is evolved for each band filter. The output images showed the trail of objects which is 2 to 10 pixels long in case of Near Infrared Spectrometer and Photometer instrument. To find out the flux distribution in the trail, the differential photometry is performed. The variation in magnitude was observed at least of 1% to 3% of the magnitude which may also implies that variation in brightness of objects can be observed with the velocity. To detect the moving objects, differential astrometry is also performed, which provides the catalogue with the information of position and proper motion of the objects as well as an image is also generated which showed the detected and undetected objects from all bands in one image.

Le travail réalisé au cours de ma de thèse avait pour but de placer de nouvelles contraintes sur la composition du ou des précurseurs organiques présents dans la nébuleuse proto-solaire. Des expériences de thermodégradation ont été mises en place en utilisant des matériaux modèles riches en azote. La spectrométrie de masse à haute résolution (Orbitrap) à été utilisée afin de mieux caractériser les polymères de HCN, autre matériau modèle. Ce travail apporte de nouvelles informations sur la diversité moléculaire de tels matériaux, ainsi que de nouvelles informations sur leur structure. Les expériences de thermodégradation proprement dites ont ensuite été réalisées, afin de mieux comprendre le comportement de l'azote dans les matériaux organiques macromoléculaires, et ainsi apporter de nouvelles contraintes sur l'origine de la matière organique présente dans les différentes classes de cosmomatériaux (chondrites carbonées, IDPs et UCAMMs). Cette série d'expériences nous a permis de mettre en évidence une probable différence de précurseur entre la matière carbonée des IOMs et celle des IDPs et UCAMMs. / The aim of my PhD work was to add some new constraints on the organic precursors compositions in the early solar system. Thermal degradation experiments have been performed, using N-rich analog materials. High resolution mass spectrometry gives us the possibility to better characterize the HCN polymers another type of analog materials. This part of the study provides us new informations about the molecular diversity of HCN polymers and also new constraints on their structure. The thremal degradation experiments were then performed. The aim of this study was to provide some new constraints on the composition of the organic precursors present in the early solar system and incorporated in the different bodies (carbonaceous chondrites, IDPs, UCAMMs). We can conclude that the organic precursor of the IOMs was poor in nitrogen while the organic matter accreted by the parent bodies of IDPs and UCAMMs was probably nitrogen rich.

The small-body populations of the distant Solar System inform our understanding of the structure, formation, and evolution of the Solar System. The orbits of these Trans-Neptunian Objects (TNOs) act as tracers for dynamical activities either ongoing or past. The distributions of TNO sizes are set by, and so probe, the conditions of the formation and evolution of the Solar System. Using data from surveys on the Canada-France-Hawaii Telescope, I constrain the size distribution of a TNO subpopulation: the scattering TNOs. The scattering TNOs are chosen as they have orbits that come in closer to the Sun, therefore allowing smaller TNOs to be detected. The characteristics of size distribution for the small-sized TNOs is an important, and only recently observable, constraint on the formation of this population. I find that the H-distribution is consistent with models where TNOs form as large (50 km - 100 km) aggregates from the proto-planetary nebula. A recent discovery of apparent clustering in the orbits of some TNOs has led to the hypothesis of an additional and unseen planet in the distant Solar System. I examine the formation implications and consequences of such a planet, and the biases in the detected sample used to infer the planet's existence. Via a combination of dynamical simulations, survey simulations, and statistical comparisons of the observed TNOs, I explore the additional planet hypothesis to determine if there exists strong evidence for an additional planet in our Solar System. I find that there is currently no strong evidence for the clustering of orbits in the observed sample and that the proposed additional planet does not produce such a signature in models. / Graduate

This paper examines the neutral coma of comet 67P/Churyumov–Gerasimenko by using measurements of charged particles (water ions) and tracing them back to their place of ionisation. The measurements were taken from Rosetta’s Ion Composition Analyser. The simulations made use of an existing program which traces particles forward, which was changed to trace particles backwards, with new conditions for terminating the simulation. Two types of simulations were made. The first type is referred to as ”one-day simulations”. In these, simulations are made using data from a single occasion, with nine occasions studied per selected day. The days were selected so that the spacecraft was in different positions in relation to the comet. The second is referred to as the ”full-hemisphere” simulation. In this simulation, data from all usable days are used to produce an image of the hemisphere facing the Sun. The full-hemisphere simulation suffers from lack of simultaneous measurements, and indeed it is impossible to obtain in-situ measurements at all positions at once. Both simulations could be improved using more precise models, which could not be done within the allotted time of this work.

The increasing number of discovered extra-solar planets opens a new opportunity for studies of the formation of planetary systems. Their diversity keeps challenging the long-standing theories which were based on data primarily from our own solar system. Resonant planetary systems are of particular interest because their dynamical configuration provides constraints on the otherwise unobservable formation and migration phase. In this thesis, formation scenarios for the planetary systems HD128311 and HD45364 are presented. N-body simulations of two planets and two dimensional hydrodynamical simulations of proto-planetary discs are used to realistically model the convergent migration phase and the capture into resonance. The results indicate that the proto-planetary disc initially has a larger surface density than previously thought. Proto-planets are exposed to stochastic forces, generated by density fluctuations in a turbulent disc. A generic model of both a single planet, and two planets in mean motion resonance, being stochastically forced is presented and applied to the system GJ876. It turns out that GJ876 is stable for reasonable strengths of the stochastic forces, but systems with lighter planets can get disrupted. Even if a resonance is not completely disrupted, stochastic forces create characteristic, observable libration patterns. As a further application, the stochastic migration of small bodies in Saturn’s rings is studied. Analytic predictions of collisional and gravitational interactions of a moonlet with ring particles are compared to realistic three dimensional collisional N-body simulations with up to a million particles. Estimates of both the migration rate and the eccentricity evolution of embedded moonlets are confirmed. The random walk of the moonlet is fast enough to be directly observable by the Cassini spacecraft. Turbulence in the proto-stellar disc also plays an important role during the early phases of the planet formation process. In the core accretion model, small, metre-sized particles are getting concentrated in pressure maxima and will eventually undergo a rapid gravitational collapse to form a gravitationally bound planetesimal. Due to the large separation of scales, this process is very hard to model numerically. A scaled method is presented, that allows for the correct treatment of self-gravity for a marginally collisional system by taking into account the relevant small scale processes. Interestingly, this system is dynamically very similar to Saturn’s rings.

Results of I-Xe analyses have been obtained from meteorite samples that experienced different extents of thermal processing in the early Solar System in order to help characterise the movements of iodine and xenon in the early Solar System and constrain the timing of these movements using the I-Xe chronometer. Samples were irradiated to convert 127I to 128Xe* and allow simultaneous measurements of iodine and xenon isotopes. Xe isotopes were measuring using the RELAX mass spectrometer.I-Xe ages of material of different metamorphic grade from R-chondrites NWA 6492, NWA 830 and NWA 3364 suggest a link between the time of closure to Xe-loss and extent of metamorphism on the R-chondrite parent body. However, further I-Xe analyses of R5 material from NWA 6492 and R4 and R6 material from other R-chondrites are needed to confirm this. The most primitive material analysed give I– Xe ages between 4559 – 4554 Myr, slightly later than reported Mn-Cr ages. This may support the ideal of radial heterogeneity of 53Mn in the early Solar System. However differences could also be due to variations in the samples analysed. Future analyses of I-Xe and Mn-Cr ages in mineral separates from the same R-chondrite are recommended in order to investigate this hypothesis. Closure to Xe-loss in chondrules on the R-chondrite parent body appears to have occurred ~5 – 10 Myr later than on the ordinary and enstatite parent bodies. This implies either later accumulation of material or slower cooling in a larger body.Comparisons of I-Xe systematics in anomalous eucrites Bunburra Rockhole and Ibitira and “nomalous” eucrites Juvinas and Béréba show lower 129I/244Pu ratios in the “nomalous” eucrites. This is not due to formation on a less volatile-rich body but instead reflects extended loss of Xe on 4 Vesta. 129I/244Pu ratios indicate igneous processing continued on 4 Vesta for ~50-100 Myr after geological activity had ceased on the anomalous eucrites parent bodies. The extended processing seen in Juvinas and Béréba is attributed to formation on a larger body that retained heat for longer. If, as the data suggest, the anomalous eucrites formed on a separate parent body it must have been catastrophically disrupted as Vesta is thought to be the only remaining differentiated asteroid. The larger size of Vesta may explain why it has uniquely survived the impacts that destroyed its siblings. Analyses of the unique achondrite GRA 06129 show that the I-Xe system in this meteorite has no chronological significance. The data instead suggest that iodine-bearing plagioclase formed early but thermal metamorphism resulted in loss of 129Xe* from iodine bearing sites. Uranium-bearing apatite appears to be a secondary mineral that incorporated parentless 129Xe* and 129Xe*that had been redistributed during earlier metamorphism. A trapped-Xe component released at high-temperatures may be a primitive component such as Q-Xe, though terrestrial–Xe acquired during weathering cannot be ruled out by this study. If Q-Xe is present, it is most likely hosted in a primary phase other than plagioclase. During its terrestrial residence time GRA 06129 acquired iodine via Antarctic weathering. I-Xe analyses on Antarctic meteorites should therefore be carried out with caution. Further Xe analyses of mineral separates from GRA 06129 would help constrain the host phase of the trapped Xe. That the I-Xe system of the plagioclase has been completely reset make it a good candidate mineral for I-Xe dating of primary processes whereas I-Xe dating of apatite appears more problematic.

Nesta tese estudamos algumas regiões de aparente estabilidade no cinturão de asteróides e no cinturão de Kuiper, analisando a evoluçãao dinâmica dos objetos nessas regiões por intervalos de tempo muito longos, em geral, da ordem da idade do Sistema Solar. Centramos principalmente nossa atenção no estudo das populações de pequenos corpos ressonantes, analisando três exemplos diferentes: a ressonância 2/1 com Júpiter e seu entorno (falha de Hecuba), a ressonância 2/3 com Netuno (Plutinos), e a ressonância 1/1 com Júpiter (Troianos). Atacamos o problema com diferentes ferramentas numéricas e analíticas: integração numérica direta de modelos precisos, modelos estatísticos de caminhada aleatória, modelos semi-analíticos baseados no desenvolvimento assimétrico da função perturbadora, cálculo de expoentes de Lyapunov, análise de freqüências, determinação de elementos próprios e taxas de difusão, etc. Os resultados obtidos permitem elaborar conclusões sobre a possível origem e evolução dinâmica destas populações. / In this thesis, we study some regions of regular motion in the asteroid main belt and in the Kuiper belt. We analyze the dynamical evolution in these regions over time scales of the order of the age of the Solar System. We centered our study on the populations of resonant minor bodies, discussing three examples: the 2/1 mean motion resonance with Jupiter (Hecuba gap), the 2/3 resonance with Neptune (Plutinos), and the 1/1 resonance with Jupiter (Trojans). We attack the problem with several different tools, both analytic and numeric: integration of N-body models, random-walk statistical models, semi-analytical models based on the assymetric expansion of the disturbing function, calculation of the maximum Lyapunov exponent, frequancy analysis, estimates of the diffusion of proper elements, etc. The results allow to draw conclusions about the possible origin of these populations.

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...

The diploma thesis studies the elaboration of project about thermal solar systém for all- season service. System is used for heating of outdoor pool and in the winter season for the heating of nearby garage in the village Lipůvka. The aim of the work was to make a proportioning, choosing the right parts and calculating the economic and ecologic balance.