<p dir="ltr">Here we present two studies of different aspects of meteoritic impacts. The first study is about the behavior of ejecta plumes after a hypervelocity impact onto a body with an atmosphere. The second study looks at the effect vaporization has on meteoroids as they descend through Earth's atmosphere, specifically the effect permeability and meteor size have on the vaporization during their explosive fragmentation.</p><p dir="ltr">Atmospheres play an important role in ejecta deposition after an impact event. Many impact experiments and simulations neglect the effect of atmospheres. In the first study, we simulate ejecta plumes created by craters with transient diameters of 2 km and 20 km on Mars and Earth to show the difference atmospheric density and crater size have on the strength of the interaction. The interaction of ejecta with an atmosphere is explored in this study using a two-fluid hydrocode that simultaneously simulates ejecta and atmospheres as coupled, continuum fields to correctly capture the transfer of mass, energy, and momentum between the two. Here we study the effect of vaporization of plume material as well as the effect of the bow shock. We find that only the fastest ejecta is vaporized with a peak vaporized mass of 2.5x10⁵ kg, 3.5 s after the impact in our 2 km diameter Terrestrial crater. Terrestrial meteorites are preferentially formed from the fastest ejecta. However, that fastest ejecta is mostly vaporized in our simulations, so to form a Terrestrial meteorite there must be a sufficiently large impact for solid material to be ejected and not vaporize. Thus, we place a lower limit of 33 km on the size of crater needed to generate terrestrial meteorites, but the crater size needed could be substantially larger. The bow shocks in our simulations result in lofting of ejecta, especially vaporized material, in the wake of the impactor. We find that Mars' thin atmosphere slows the ejecta but does not significantly change the trajectory of the plume. Earth's atmosphere can stop and entrain ejecta particles to suspend heated material long after the majority of material has already been deposited, resulting in 4x10¹⁰ kg of material being suspended in the atmosphere 100 seconds after the impact for a 2 km diameter crater. For larger craters, we find that Earth's atmosphere has a more limited effect and ejecta more closely follows a ballistic trajectory.</p><p dir="ltr">The 1908 Tunguska bolide event and the 2013 Chelyabinsk bolide event underscore the potential damage posed by relatively small meteoroids as compared to the dinosaur-killing Chicxulub meteoroid. In this study, we model Tunguska- and Chelyabinsk-sized bolide events, extending the work of Tabetah and Melosh (2018) by exploring a larger parameter space and introducing the novel feature of material vaporization. Building upon their findings that the porosity and permeability of a meteoroid significantly influence fragmentation, we investigate additional factors such as meteoroid size, entry speed, and entry angle. Furthermore, we demonstrate that vaporization plays a crucial role, lowering the fragmentation height by extracting energy through latent heat. We find that a larger meteoroid size or higher entry speed increases the amount of vaporization that occurs while lowering the altitude of disruption of the meteoroid, and that a shallower entry angle decreases the amount of vaporization and increases the altitude of disruption. Our study not only refines the understanding of bolide events but also introduces a novel perspective with potential implications for planetary science and impact risk assessment.</p>

<p dir="ltr">We present a model describing an impact jetting origin for the formation of chondrules, the mm– scale, igneous components of chondritic meteorites which originated during the first few million years of solar system history. The ubiquity of chondrules in both non-carbonaceous and carbonaceous chondrites suggests their formation persisted throughout the protoplanetary disk, but their formation mechanism is debated and largely unexplored in the outer disk.<b> </b>Using the iSALE2D shock physics code, we generate models of the process of impact jetting during mixed material (dunite and water ice) impacts that mimic accretionary impacts that form giant planet cores. We show that the process of impact jetting provides the conditions necessary to satisfy critical first-order constraints on chondrule characteristics (size, shape, thermal history). We then explore the implications of chondrule formation by impact jetting during the formation of giant planet cores by combining the original results with simulations of giant planet core accretion generated using a Lagrangian Integrator for Planetary Accretion and Dynamics (LIPAD) code.</p><p dir="ltr">The second closest Galilean satellite to Jupiter is Europa, an ocean world with an outer ice shell and subsurface water ocean encapsulating its rocky core. The surface of Europa is covered in double ridges. These features are defined by two topographic highs about 100 meters tall, with a central trough between them, which extend for hundreds of kilometers over the surface of the moon. Accurate models for the formation of features as prominent as double ridges will help to further constrain the interior structure and dynamics of the interior of the body. We use analytical and numerical finite element models to show that the incremental growth of an ice wedge within the ice shell can cause deformation matching the observed size and shape of observed double ridges on Europa. These models indicate that the total height and width of the ridges correspond to the depth of the wedge, so that deeper wedges create shorter and broader ridges. We consider different sources for the wedge material and ultimately argue in favor of local sources of liquid water within the ice shell.</p>

<p dir="ltr">The climate and habitable potential of a planet is controlled in part by its orbital configuration, including its obliquity, eccentricity, rotation period, and separation from the host star. Recent studies have suggested the exoplanets with higher eccentricity or obliquity than Earth might be able to produce larger biospheres, potentially leading to "super-habitable" worlds. However, high-obliquity and high-eccentricity planets have also been shown to be susceptible to increased water loss, which would decrease the habitable lifetime.</p><p dir="ltr">I use ExoPlaSim, a 3D General Climate Model, to investigate the habitable lifetimes of a diverse range of possible orbital configurations by varying the planetary obliquity (0-90^o), eccentricity (0-0.4), rotation period (6-96 hr), and stellar constant (1350-1650 W/m²). I study each orbital parameter independently while also co-varying obliquity with eccentricity and rotation period for the entire range of stellar constants. I find that stellar constant is the primary control on atmospheric water vapor, but also that the planetary obliquity, eccentricity and rotation period can determine the escape regime. Increasing the obliquity or eccentricity can push the climate into the significant escape regime at lower stellar constants relative to low-obliquity or low-eccentricity planets. Increasing the rotation period at high obliquities maximizes the habitable lifetime of an exoplanet.</p>

Compositional characterization of lunar surface features informs our understanding of the Moon's thermal and magmatic evolution. We investigated the compositions of hypothesized volcanic features known as irregular mare patches (IMPs) and their surroundings to constrain formation mechanisms. We used six datasets to assess the composition of 12 IMPs: 1) Moon Mineralogy Mapper (M3) derived spectral parameters (e.g., band center positions, shapes), 2) Lunar Reconnaissance Orbiter (LRO) Diviner Radiometer Experiment (Diviner) measured Christiansen feature (CF) position, 3) SELENE (Kaguya) Multiband Imager (MI) FeO abundance, 4) Clementine 5-band (Ultraviolet/Visible)-derived FeO abundance, 5) LRO Wide Angle Camera (WAC) TiO2 abundance, and 6) LRO Narrow Angle Camera (NAC) derived single scattering albedo. Our analysis suggests that some IMPs are compositionally unique from their surroundings, while other IMPs exhibit ambiguous compositional trends, which is consistent with the wide variety of geologic settings in which IMPs are situated. Large IMPs are similar to surrounding low albedo dark halos, which could suggest a formation association between IMPs and these dark halo materials. Spectral and photometric comparisons suggest that IMPs' compositions are compatible with Apollo 11 and 17 high-Ti mare basalts, as well as a group of synthetic high-Ca pyroxenes. Future remote sensing orbiters with high spatial resolution are essential to resolve the compositions of smaller IMPs as well as the distinct smooth and rough morphological regions within larger IMPs.

Light curve inversion is a standard method to determine shapes, rotation periods and spin axis orientations of asteroids. This method can be extended to determine the size, albedo, thermal inertia and surface roughness parameters of an asteroid by including observations in thermal infrared. A solution of the Heat Conduction Equation (HCE) is necessary to model infrared flux from the asteroid. We analyse the accuracy requirements of the extended method for numerical solution of the HCE. We show that current implementation leads to errors in flux that are substantial. We recommend changes in the current implementation of the HCE solving approach to address the accuracy issues. We discuss uniqueness and stability of the solutions produced by the extended method as well as the accuracy of the determined parameters and their stability. Shapes of asteroids are produced and their physical attributes are determined based on light curve and infrared data.

Les domaines millimétrique et submillimétrique sont des domaines qui permettent de caractériser la physico-chimie des atmosphères <br />planétaires par l'observation des molécules qui les composent. Le télescope spatial Herschel et l'interféromètre ALMA, qui <br />entreront prochainement en service, permettront d'améliorer considérablement notre connaissance des atmosphères planétaires.<br /><br />L'un des principaux objectifs de cette thèse est de développer un modèle d'analyse des observations millimétriques et submillimètriques qui seront effectuées avec Herschel et ALMA. C'est en ce sens que nous détaillons un modèle qui tient compte de la géométrie sphérique des corps observés et des spécificités instrumentales propres aux télescopes utilisés. <br /><br />Dans un premier temps, ce qui a permis notamment de valider notre modèle de transfert radiatif, nous avons étudié l'origine des <br />composés oxygénés dans les atmosphères des planètes géantes. Nous présentons l'analyse d'observations de Saturne et d'Uranus, effectuées avec les télescopes de l'IRAM et du JCMT, pour contraindre les sources de monoxyde de carbone dans ces atmosphères. Nous améliorons ainsi les limites supérieures précédemment publiées et réalisons la première observation du monoxyde de carbone dans l'atmosphère de Saturne dans <br />le domaine submillimètrique. Cette observation prouve l'existence d'une source externe pour ce composé. Nous analysons également des observations récentes de Jupiter, effectuées par le télescope spatial Odin, pour contraindre l'origine externe de l'eau dans la stratosphère de cette planète. Les observations confirment que la chute de la comète Shoemaker-Levy~9 est vraisemblablement la source principale d'eau. <br /><br />Dans un second temps, nous avons appliqué notre modèle à l'étude de la structure thermique et la dynamique de l'atmosphère de Mars, à partir d'observations du monoxyde de carbone. Ces observations sont comparées aux prédictions d'un modèle de circulation générale, ce qui permet de vérifier la validité de ses prédictions et de fournir de nouvelles contraintes observationnelles pour ce type de modélisations.<br /><br />Enfin, nous avons appliqué notre modèle à l'étude des planètes géantes avec le télescope spatial Herschel, dans le cadre du programme-clé de temps garanti du télescope spatial Herschel "Water and related chemistry in the Solar System''. Nous avons également identifié les améliorations à apporter à notre modèle pour analyser des observations ALMA.

Interactive application for teaching the topic of the Earth as a planet Abstract The thesis is focused on the creation of an interactive application for teaching the topic of the Earth as a planet at secondary schools. The theoretical part generally deals with digital technologies for teaching, educational applications and pedagogical-psychological aspects of the subject. The topic was defined and analyzed using curriculum documents, textbooks and school atlases. Based on the analysis, partial topics were selected and turned into an application that covers separate learning objects. 8 learning objects were created ("Distances and dimensions", "Earth's orbit", "Seasons", "Solar time", "Moon phases", "Solar and Lunar eclipses", "Orbiting around the barycenter", "Tidal phenomena") and 4 learning objects were taken ("Solar System", "Earth's shape - geoid", "Time zones", "Future eclipses"). Each learning object has been provided with its theoretical introduction and methodological questions and tasks. The final educational application will be available on the Internet as a web application, without the need for installation. Keywords: educational application, interactivity, teaching Geography, the Solar System, the Earth, the Moon

The diploma thesis studies the elaboration of project about optimization of solar system for all- season service. The aim of the work was to make a proportioning, choosing the right parts and finding the economic and ecologic balance.

This master’s thesis deals with design of the regulation of a circulating pump in a solar system for heating of supply water and design of the regulator for this system. It describes a fundamental principle and layout of a regulated circuit of a heating system. Description of regulation, basic terms, properties and differences between different types of regulation are described in first part of the master’s project. Especially continuous (PID regulator) and discrete (PSD regulator) regulation are presented. Second part of the master’s project is focused on a conceptual design of the circulating pump regulator. The connection system of each part, selection conditions of components and connection scheme of regulator are described. The third section deals with design of controlling algorithm of the regulator. There is a detailed description of libraries and functions in each chapter which were used in programming of PSD regulator algorithm. The regulated system of a solar collector is described at the end of the work. This system is being developed for real testing and setting of regulator.

The aim of this Diploma thesis is the design of solar collectors. The thesis is consists from three parts. The first part describes the technical design of solar collectors and solar systems. The second part contains with design size of the collector area for the two selected variants. The third part addresses the experimental measurements located on the real building. The output of third part is the economic evaluation of the solar system.