Tesi sul tema "Corps planétaires"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-15 saggi (tesi di laurea o di dottorato) per l'attività di ricerca sul tema "Corps planétaires".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi le tesi di molte aree scientifiche e compila una bibliografia corretta.
Sezestre, Elie. "Les poussières et petits corps des systèmes planétaires extrasolaires". Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY022/document.
During my thesis, I numerically simulated the dynamical behaviour of dust and small grains around stars, applied to two ranges of stellar distance : debris disks and exozodis.Concerning debris disks, I focused on the fast moving arch-like structures observed over 15 years inside the disk of AU Mic. Supposing that they all come from a single parent body and that the dust composing the arches have the same dynamics, I showed that the parent body must be closer-in than the planetesimal belt (<25 au), on a circular orbit or static with respect to the observer. Grains must be submicronic in order to explain the apparent velocity of the arches, gained by means of stellar wind pressure. Large-scale magnetic field of the star is large enough to explain the vertical extent of the arches, but require further investigations.I also developped a numerical code in order to test the dynamical origin of dust composing exozodis, to compare its results to the observations. I showed that the classical PR-drag scenario involving grains drifting inward from a distant cold parent belt produce an excess flux in mid-infrared compared to the near-infrared, unbalanced by the pile-up. The cometary scenario, by producing dust very close to the star, emits less in mid-infrared. A ten of kilometric comets can reproduce the flux levels observed around all stars. This numerical code is also able to handle the DDE, the stellar wind pressure or the magnetic field.During my work, I showed that taking into account the dust dynamics can constrain the dust physical properties. I developped adaptative numerical tools that can handle the variety and complexity of dust observed around stars
Farago, François. "Quelques aspects de la dynamique des systèmes planétaires extrasolaires". Observatoire de Paris (1667-....), 2010. https://hal.science/tel-02094983.
The doctoral thesis presents analytical methods to study the dynamics of systems of bodies under their mutual gravitational interactions. It is motivated by the great diversity of properties and behaviors exhibited by extrasolar planetery systems. However, the methods which we present here can also apply in other contexts such as the study of multiple stellar systems or the study of stellar populations around compact objects in the galactic center. We widely use secular models because they allow a simplification in the equations as well as a considerable speed-up in numerical computations. This last aspect is critical when a large set of initial conditions must be explored. We first derive a semi-secular model which is adapted to the study of a system where one of the bodies is much closer to the central body than the other ones. This model is illustrated on the multi-planetary system around mu Arae. The vectorial formalism used throughout this doctoral work is also introduced. The second part of this thesis studies the quadripolar and secular three-body problem. Al ready explored by Ferrer and Osacar (1994), it is an integrable problem. We give a formulation of the problem which allows it to be very easily connected to its to extreme interior (Kozai, 1962) and exterior (Palacian, 2006) cases. We use this formulation to explain the results obtained by Verrier and Evans (2009). The last part of the thesis focuses on the addition of tidal interactions in systems dominated by Kozai's mechanism. We derive a model of this situation and apply it to the case of HD 80606b which is the most eccentric extrasolar planet discovered with an eccentricity of e=0. 93
Sonzogni, Yann. "Les inclusions magmatiques : des cinétiques de croissance cristalline à la formation des corps planétaires". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00657302.
Charnoz, Sébastien. "Contribution à l'étude des disques planétaires et protoplanétaires perturbés". Paris 7, 2000. http://www.theses.fr/2000PA077039.
Besserer, Jonathan. "Approche numérique du couplage par effets de marée entre transferts thermiques internes et évolution orbitale des corps planétaires". Nantes, 2012. https://archive.bu.univ-nantes.fr/pollux/show/show?id=f0de8511-7668-460e-824c-00b47c604729.
Tidal effects that occur in some objects of the Solar System, and probably in a great part of the extrasolar planets detected so far, associate the viscous friction induced by the periodic deformation of their internal, possibly external layers (atmosphere and oceans), to a change of their orbital parameters. Since tidal dissipation strongly depends on rheology, hence on temperature, there is a natural coupling between these effects and heat transfer inside planetary bodies. This thesis was devoted to the building of a numerical model that self-consistently simulates thermal convection in a compressible mantle with variable viscosity and subjected to heterogeneous tidal heating, and the orbital evolution of the body. Conservation equations for mantle dynamics are treated by a finite volume method based on the bi-dimensional spherical annulus geometry; this approach approximates three-dimensional heat transfer while keeping moderate computational time. In particular, a multigrid mechanical solver and a high resolution advection scheme for the heat equation were implemented. The dissipation of tidal energy, which influences orbital evolution, is then computed through a semi-analytical solution derived during this work. Two preliminary applications are presented to investigate, on one hand the influence of compressibility in the treatment of the convection problem coupled with tidal dissipation and, on the other hand the effect of this coupling on orbital evolution
Boyet, Maud. "Anomalies isotopiques du système 146Sm-142Nd : Evolution précoce et dynamique interne de la Terre et d'autres corps planétaires différenciés". Lyon, École normale supérieure (sciences), 2003. http://www.theses.fr/2003ENSL0258.
Morard, Guillaume. "Les systèmes Fe-FeS et Fe-S-Si à haute pression et haute température : implications pour les noyaux des corps planétaires". Paris, Institut de physique du globe, 2006. http://www.theses.fr/2006GLOB0011.
Niederman, Laurent. "Résonances et stabilité dans le problème planétaire : solutions de seconde espèce". Paris 6, 1993. http://www.theses.fr/1993PA066615.
Robutel, Philippe. "Contribution à l'étude de la stabilité du problème planétaire des trois-corps". Observatoire de Paris (1667-....), 1993. https://hal.science/tel-02153557.
Deligny, Cécile. "Origine des éléments volatils et chronologie de leur accrétion au sein du Système Solaire interne : Apport de l'analyse in-situ des achondrites". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0329.
Volatile elements such as hydrogen and nitrogen control the evolution of planetary bodies and their atmospheres, and are essential elements for the development of life on Earth. Nevertheless, the origin of volatile elements and the timing of their accretion by terrestrial planets formed in the inner solar system remains a subject of debate and controversy in planetary science. To answer these questions, the isotopic ratios of hydrogen (D/H) and nitrogen (15N/14N) are powerful tools to trace the origin (solar, chondritic or cometary) of volatile elements trapped in planetary bodies. Therefore, to constrain the source(s) of volatile elements trapped in rocky planets, we analyzed hydrogen and nitrogen contents and isotopic compositions by ion microprobe (LGSIMS) in achondrites that originate from asteroids or from planets that are assumed to have formed in the inner solar system. These meteorites preserve a record of the initial stages of the formation of their parent bodies and can constrain the early evolution of planetary volatile elements. In-situ analysis by SIMS is a quasi-non-destructive technique, which permits to measure the abundance and the isotopic composition of volatile elements of different phases in terrestrial, extraterrestrial and synthetic samples. The recent development of the protocol of nitrogen analysis in silicate samples by ion probe allows us to target tens of micron- sized objects (i.e., glassy melt inclusions). Volatile elements were measured in melt inclusions trapped in minerals and in interstitial glasses. Although the analysis of nitrogen in aubrites was unsuccessful, the analysis performed on Martian meteorites and angrites revealed the presence of a large amount of water and nitrogen within these meteorites. In particular, the study of angrites and more precisely the meteorite D'Orbigny allowed us to highlight the presence of water and nitrogen having isotopic composition similar to those of the primitive meteorites formed in the outer solar system (i.e., CM-like carbonaceous chondrites). These results imply that these volatile elements must have been present in the inner solar system within the first ~4 Ma after CAI formation (i.e., the first solids to form in the solar system) and may have been trapped by the terrestrial planets during their formation. Furthermore, the analysis of Martian meteorites and more particularly of Chassigny revealed the presence of nitrogen with an isotopic composition enriched in 15N compared to enstatite chondrites and terrestrial diamonds which are believed to record the most primitive value of nitrogen on Earth
Belley, Katia. "Détection de sites sécuritaires par réseaux de neurones pour un atterrissage autonome sur corps planétaire". Mémoire, Université de Sherbrooke, 2008. http://savoirs.usherbrooke.ca/handle/11143/1447.
Olmicia, Sébastien. "Détermination de la vitesse relative d'une sonde par réseaux de Kohonen lors d'une phase d'atterrissage autonome sur un corps planétaire". Mémoire, Université de Sherbrooke, 2005. http://savoirs.usherbrooke.ca/handle/11143/1290.
Faramaz, Virginie. "Dynamique des systèmes exoplanétaires". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENY045/document.
At least 20% of Main-Sequence stars are known to harbor debris disks analogs to the Kuiper Belt. These disks are proof that the accretion of solids has permitted the formation of at least km-sized bodies. It is thus not surprising that several of these disks are accompanied by planets, which may reveal themselves by setting their dynamical imprints on the spatial structure of debris disks. Therefore, the detection of an eccentric debris disk surrounding Zeta² Ret by the Herschel space telescope provides evidence for the presence of a massive perturber in this system.Zeta² Ret being a mature Gyr-old system, and in that sense, analogous to our own Solar System, it offers a different example of long-term dynamical evolution. This thesis includes a detailed modeling of the structure of the debris disk of Zeta² Ret, which leads to constraints on the mass and orbital characteristics of the putative perturber. This study also reveals that eccentric structures in debris disks can survive on Gyr timescales.Detailed modeling of the structure of debris disks can allow the posterior discovery of hidden planets as is the case for the Fomalhaut system. The eccentric shape of the debris disk observed around this star was first attributed to Fom b, a companion detected near the belt inner-edge, which revealed to be highly eccentric (e~0.6-0.9), and thus very unlikely shaping the belt. This hints at the presence of another massive body in this system, Fom c, which drives the debris disk shape. The resulting planetary system is highly unstable, which involves a recent scattering of Fom b on its current orbit, potentially with the yet undetected Fom c. This scenario is investigated in this thesis and its study reveals that by having resided in inner mean-motion resonance with a Neptune or Saturn-mass belt-shaping eccentric Fom c and therefore have suffered a gradual resonant eccentricity increase on timescales comparable to the age of the system (~440 Myr), Fom b could have been brought close enough to Fom c and suffered a recent scattering event, which, complemented by a secular evolution with Fom c, explains its current orbital configuration. This three-step scenario also implies that significant amounts of material may have been set on extremely eccentric orbits such as this of Fom b through this mechanism, which in return could feed in dust the inner parts of the system. Therefore, this mechanism may also explain the presence of inner dust belts in the Fomalhaut system, but also the discovery a significant population of very bright hot dust belts in systems older than 100 Myr.The planetary systems discovered so far exhibit a great variety of architectures, and our solar system is far from being a generic model. One of the main mechanism that determines a planetary system morphology is planetary migration. The presence of a stellar binary companion - which our solar system is deprived of - is expected to affect planetary migration conditions, and potentially lead to the formation of very different planetary systems. This phenomenon is obviously non-negligible since binary systems represent at least half of stellar systems. At late stages of planetary systems formation, planetary migration may occur as the result of interactions with remaining solid planetesimals and the impact of binarity on this planetesimal-driven migration is explored in this thesis. A stellar binary companion may in fact reverse the tendency for planets in single star systems to migrate inwards, and bring them closer to regions perturbed by the binary companion, where they could not have formed in situ. This may give an explanation for the presence of planets which present signs of outward migration towards a circumstellar companion in the Gamma Cephei and HD 196885 systems
Cabrera, Juan. "Préparation des observations de planètes extrasolaires". Phd thesis, Observatoire de Paris, 2008. http://tel.archives-ouvertes.fr/tel-00363365.
Cabrera, Juan. "Préparation des observations de planètes extrasolaires". Phd thesis, Observatoire de Paris (1667-....), 2008. https://theses.hal.science/tel-00363365.
The first part of this thesis considers the three body problem. In a first approximation of the hierarchical restricted three body problem, it is studied the motion of a star gravitationally linked to a distant binary. This perturbation can mimic the reflex motion of a star caused by a planet, provoking a false detection by astrometric or radial velocity methods. Then, in the case of a multiple planet system, the perturbations in the time of arrival of the transit signals as well as their influence in the planetary detection are considered. Next, the photometric signal produced by a stellar spot is analyzed to recognize its differences with planetary transits : in some configurations spots can produce a similar signal. The techniques developed are applied to the study of planetary photometry. In particular, the mutual phenomena between a planet and a satellite (occultations and projections of shadows) are examined and the detailed analysis of the signal of a transit. Finally, an important part of the thesis has been devoted to the analysis of the data supplied by the mission CoRoT, committed to the search for extrasolar planets. Four times a year, the satellite furnishes ten thousand light-curves that must be filtered of instrumental noise and stellar activity prior to the search for planetary signals. Eventually, the candidates are followed photometrically and spectroscopically from ground to determine their mass. In the systems where a planet has been found, the time of arrival of the transits is studied looking for the perturbations described in the first part of the thesis