WorldCat Identities

Beck, Pierre (1980-....).

Overview
Works: 14 works in 16 publications in 2 languages and 17 library holdings
Roles: Thesis advisor, Other, Opponent, Author
Publication Timeline
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Most widely held works by Pierre Beck
Etude d'une série de micrométéorites antarctiques : caractérisation multi-analytique et comparaison à des chondrites carbonées by Manon Battandier( )

1 edition published in 2018 in French and held by 2 WorldCat member libraries worldwide

The study of the Solar System's small bodies (asteroids and comets), formed 4.567 billions years ago, gives us an insight on the materials initially present in the solar nebula and on the mechanisms operating in the primitive Solar System. This study can be performed via the analysis of the so-called primitive cosmomaterials, as meteorites (mainly chondrites), interplanetary dust particles (IDPs) or even micrometeorites.This PhD thesis consists of a multi-analysis of a series of 58 Antarctic micrometeorites (AMMs) from the CONCORDIA 2006 and 2016 collections. This set of AMMs provides a large range of textural types reflecting different intensities of heating experienced during the entry in the atmosphere : 40 unmelted fine-grained particles (Fgs), 12 particles intermediate partially melted (Fg-Scs), 1 partially melted scoriaceous particle (Sc) and 5 completely melted cosmic spherules (CSs). To study these samples, I used different analytical methods : i) Raman spectroscopy, to study the structure of the polyaromatic organic matter; ii) infrared (IR) spectroscopy, to analyze the aliphatic organic matter as well as the hydration state and the mineralogy of these samples; and iii) nanoscale secondary ion mass spectroscopy (NanoSIMS) to measure the isotopic composition of carbon and nitrogen of the organic matter contained in the AMMs. In order to constrain the diversity of parent bodies sampled by cosmomaterials, I also studied type 1 and 2 CM, CR and CI carbonaceous chondrites.The combination of Raman and IR techniques reveals differences among AMMs in terms of abundance, structure and chemical composition of the organic matter, mineralogy and hydration state. In particular, 7 Fgs distinguishing themselves from others AMMs as they show : i) a hydrated mineralogy with phyllosilicates, ii) an abundance in polyaromatic and aliphatic organic matter and iii) structural differences in the polyaromatic organic matter. Heating laboratory experiments, on CM, CR and CI carbonaceous chondrite matrices show that the atmospheric entry can induce : a dehydration of the samples, a drop in the abundance of organic material and a structural modification of polyaromatic organic matter. The identification of 17 non-hydrated Fgs reveals that, in spite of their fined-grained texture, some Fgsmay have experienced significant heating during their entry in the atmosphere. The 7 identified Fgs then appears as the ones that were the least affected by the atmospheric entry and thus the most primitive of our series. Moreover, this study shows that the hydration state, the mineralogy and the organic matter are more sensitive tracers to heating experienced during the atmospheric entry than the texture of micrometeorites.Intrinsic differences, which cannot be explained by the atmospheric entry, are also revealed between the 7 hydrated Fgs and CM, CR and CI chondrites. These differences are : i) a specific spectral signature of silicates in IR, ii) an abundance in organic and aliphatic material and iii) different characteristics of the aliphatic organic matter. Moreover, the analysis of the isotopic composition of carbon and nitrogen shows large variabilities among AMMs, in opposition with observations among carbonaceous chondrites. These intrinsic differences are explained here as AMMs and carbonaceous chondrites sampling distinct parent bodies
Pétrogénèse et métamorphisme de choc des météorites martiennes by Pierre Beck( Book )

2 editions published between 2005 and 2006 in French and held by 2 WorldCat member libraries worldwide

Microphysique des processus saisonniers des glaces de Mars et Pluton : suivi par télédétection hyperspectrale et étude expérimentale by Sylvain Philippe( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

The condensation/sublimation cycle of CO2 controls the martian climate and, in winter, forms frozen seasonal deposits, contaminated with water ice and dust. This thesis' objective is to unders- tand, characterize, and if possible, to quantify the different microphysical processes occuring in the seasonal deposits during this condensation/sublimation cycle, with the insight of experimental simulation of these processes inside the CarboN-IR experimental cell. The CO2 ice condensation in a polycristalline form on a mineral regolith, the modification of the CO2 ice condensation regime in the martian polar night due to the presence of non condensable gases, the stratification of water ice onto CO2 ice during the sublimation of the seasonal deposits and the increase of the albedo of CO2 slab ice during its springtime sublimation are all phenomena that have been reproduced successfully inside the experiemental cell. The CO2 slab ice condensation on the Martian surface has been observed during its formation, in autumn, at lower latitudes than polar night limit with hyperspectral imaging from the OMEGA spectrometer onboard of the Mars Express probe. Yet the farthest object explored in the solar system, Pluto, shares many similarities with Mars, parti- cularly a partial icy cover of its surface (of CH4, N2 and CO ices for Pluto) in equilibrium with its atmosphere. The evolution of these ices can be considered similar in terms of the surface pro- cesses affecting them : stratification of ices in function of their volatility during their sublimation or condensation at the surface, formation of slab ice ... The hyperspectral imagery data (LEISA), provided by the New Horizons probe during its Pluto's flyby in july 2015, allowed to determine the accurate cartography of chemical species at the surface, along with their physical state - the preliminary steps of any geological interpretation
Les condensats saisonniers de Mars : étude expérimentale de la formation et du métamorphisme de glaces de CO2 by Florence Grisolle( )

1 edition published in 2013 in French and held by 2 WorldCat member libraries worldwide

The current climate of Mars causes the formation of seasonal consendates on the surface of high-latitude regions during the polar night. This layer sublimates when exposed to sun in spring. Spatial instruments have enabled to study the spatial and temporal evolution and thermodynamic properties of ther CO2-mainly deposits. The aim of this thesis is to supplement this research by laboratory experimentation in order to improve the knowledge of the condensates properties and microphysical process. An experimental set-up, CARBON-IR, has been conceived to manipulate analogous ices in controlled environment. The experiments on CO2, at equilibrium or nonequilibrium, create various grainsize (from about ten microns to several millimeters) and porosity (from 0 to 50% approximately) condensates. The corresponding near-infrared reflectance spectra show specific differences. Compact CO2 slab ices, transluscent or with highly transparency, can be formed by thermal metamorphism of porous snow or by direct condensation of gas. Thermal fluxes balance in the system highlights heat fluxes supplied by the set-up to the sample and the sublimation-condensation process ocurring in it, with matter and energy transfers through the porosity. Thermal and pressure constraints on the ice samples enable to determine the evolution according to of specific parameters, and therefore to comprehend the seasonal condensates microphysic evolution associated with local thermal conditions on Mars polar regions. Accuracy of radiative transfer models and GCM, as well as interpretation of Martian monitoring data will be improved by the confrontation with the experimental results
Étude de l'altération hydrothermale des chondrites carbonées et implications pour les observations des petits corps by Alexandre Garenne( )

1 edition published in 2014 in French and held by 2 WorldCat member libraries worldwide

Les astéroïdes sont des vestiges datant de la formation de notre Système stellaire. Ils nous offrent une opportunité unique de comprendre la mécanique de formation d'un système planétaire habité, le Système Solaire. Une méthode de caractérisation de ces petits corps couramment utilisé est la spectroscopie en réflectance, qui permet à, depuis la Terre ou lors de missions spatiales, d'obtenir des informations sur la minéralogie de ces objets. L'objet de cette thèse est de participer à une meilleure compréhension de cette technique de caractérisation, ainsi que d'étudier, via les météorites, les processus d'altérations ayant modifiés la composition initiale. Pour ce faire nous avons utilisé différentes méthodes d'analyses sur des chondrites carbonées (qui proviennent d'astéroïdes primitifs) afin de caractériser leur chimie et leur minéralogie. Nous avons ainsi étudié les phases hydratées, la teneur en eau, la structure des silicates et l'état d'oxydation du fer de ces météorites. Toutes ces analyses combinées nous ont permis de mieux comprendre l'évolution de la minéralogie en fonction des processus d'altérations hydrothermaux. Ces études ont également permis d'apporter des contraintes quantitatives et qualitatives sur les caractéristiques contrôlant les spectres en réflectance de ces mêmes météorites. Nous avons étudié et comparé de nombreux paramètres entre eux pour permettre de quantifier l'eau et proposons celui qui nous semble le plus adapté pour quantifier les phases hydratés à la surface des petits corps sombres du Système Solaire
Spectrophotométrie de la matière extra-terrestre by Sandra Potin( )

1 edition published in 2020 in French and held by 1 WorldCat member library worldwide

La spectroscopie en réflectance est l'une des techniques majeures permettant d'obtenir des informations physiques et minéralogiques sur la surfaces des corps planétaires. Cependant, la réflectance d'un corps dépend fortement de paramètres extérieurs à sa surface, tels que sa température ou encore la configuration de l'éclairement et de l'observation. Le nouveau spectro-gonio radiomètre de l'IPAG, SHADOWS, a été spécialement conçu pour réaliser des mesures de réflectance bidirectionnelle de surfaces sombres et de petite taille, telles que les météorites. Ce goniomètre compte également deux cellules environnementales, MIRAGE et IceBERG, permettant de placer les échantillons étudiés dans des conditions de température et pression similaires aux petis corps du Système Solaire. L'analyse des signatures d'hydratation détectées sur des spectres de météorites en conditions astéroïdales a permis de mettre en évidence l'altération de la minéralogie due à la haute température. Un nouveau modèle de déconvolution a été utilisé pour séparer et analyse de manière indépendante les composantes de la bande à 3-µm. La comparaison entre les mesures effectuéesen laboratoire et les observations d'astéroïdes ont mis en évidence un lien entre cette signature spectrale et l'histoire d'altération aqueuse et thermique de la surface. La dépendance de la réflectance avec la géométrie de la mesure a été montré par une série d'analyse en réflectance bidirectionnelle de différentes surfaces. Ces résultats ont ensuite été appliqués sur des simulations d'astéroïde, pour montrer l'effet de la forme du corps sur son spectre intégré
Surface chemistry of molecules of astrophysical interest : theory and simulations by Joan Enrique-Romero( )

1 edition published in 2021 in English and held by 1 WorldCat member library worldwide

In this thesis I have investigated some of the critical points towards the formation of iCOMs on interstellar icy dust.In particular I have tackled the problem of the synthesis of iCOMs on the surfaces of interstellar dust grains from a theoretical point of view with quantum chemistry calculations. Such calculations have shown that radical--radical reactions on interstellar ice are (i) can have activation energy barriers mainly due to the radical--surface interaction, (ii) can have competitive channels other than the formation of iCOMs like that of direct hydrogen abstraction, in which one radical takes an H atom from the other and (iii) the occurrence of one channel or the other may entirely depend on their orientation upon encounter.These results have a strong impact in the astrochemistry community since in most cases it is usually assumed that radical--radical reactions are barrierless and that can only produce iCOMs.Another point that we have tackled in this thesis is the importance of binding energies when computing the efficiencies of radical--radical reactions, which strongly depend on the diffusion timescales, which in turn depend on the binding energies and on the diffusion-to-desorption activation energy ratio. We have shown for the formation of acetaldehyde from the coupling of CH₃ and HCO radicals the choice of the diffusion-to-desorption activation energy ratio strongly affects the conclusions, and that tunneling effects in direct H-abstraction reactions (in this case HCO + CH₃ --> CO + CH₄) can be of great importance at low temperatures. The reaction rates related to the activation energies were obtained by means of the Rice-Rampsberger-Kassel-Marcus (RRKM) theory, i.e. the microcanonical counterpart of the classical transition state theory, while the desorption and diffusion rate constants were simulating using Eyring's equation.Finally, we have also tackled the problem of the fate of the energy after a chemical reaction on top interstellar ices. We have studied how does the energy released by H + CO --> HCO and H + H -->H₂ partition in between the product molecule and the surface by means of ab initio molecular dynamics.For the former reaction, the surface was modelled by a proton ordered Ih crystalline ice in order to limit the complexity of the system (in such an ordered surface, the number of binding sites is drastically reduced to a few that periodically repeat). We found that the energy released is very efficiently absorbed and dissipated by the ice structure in about 1 ps, so that the HCO product remains frozen on the ice surface. In the case of H₂, we have studied the reaction on crystalline and on three different spots on an amorphous ice model. In all cases the ice structure absorbs about one half of the energy released upon H₂ formation, which is still not enough for H₂ to remain frozen, so that its fate is probably leave into the gas phase with a certain amount of vibrational excitation (they were found to be vibrationally excited during the first ps). The region where the H₂ molecule was formed was observed to remain energized for about 100-200 fs, so that we cannot reject the idea that the energy released by such reactions might be used by other species with low binding energies to be ejected into the gas
Serpentinisation et carbonatation de la croûte Martienne by Benjamin Bultel( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

Over the last 3 billion years liquid water has an extremely limited presence on Mars. However, the multiple data available on the planet show evidences of a significant presence of liquid water from the accretion of the planet until about 3.7 billion years. The prevailing hypothesis today is that Mars had a denser atmosphere (possibly rich in CO2) early in its history. Much of this atmosphere and water were lost in space. Another possibility for reducing the amount of liquid water available and the reduction of the atmosphere is the water storage of water and CO2 in the crust. The Martian crust is studied via CRISM spectro-imaging data to characterize the early hydrothermal alteration of the planet. Serpentine and carbonates of detections confirm that the storage of a portion of the water and the atmosphere of Mars occurred. Additional constraints are provided by the geochemical modeling of serpentinization and carbonation of the Martian crust through EQ3/6 programs. The importance of serpentinization and carbonation of the Martian crust is thus reassessed. The results allow to open the debate on the role of serpentinization and carbonation on the evolution of the liquid water available and the evolution of the atmosphere. In addition, the thermodynamic conditions help provide constraints on the exobiology potential of the Martian crust
Evolution des corps-parents des chondrites ordinaires : du sol à l'espace by Alexis Drouard( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

This thesis aims to bring new constraints on the evolution of the ordinary chondrite parent bodies by studying both meteorite flux and impact craters. The results encompass the different steps of meteorite lives, from their parent-bodies to Earth's surface including the atmospheric entry. Specifically, the dating of ordinary chondrites recovered in the Atacama Desert show that this ancient surface has continuously recorded the meteorite flux for several million years. Such timescales, in addition to the very high meteorite density of this region, imply that the Atacama Desert is a preferential area to constrain the collisional evolution of the ordinary chondrite parent-bodies. On another note, the analysis of high-resolution spectra acquired during meteorite ablation experiments changes the expectations for meteor spectroscopy's capacity to determine the composition of the current flux by using camera networks. Meteor spectro- scopy does not seem capable of distinguishing meteorite sub-groups but only major classes (chondrites, achondrites, irons). Concerning large asteroids, the adaptative optics in the visible range on the VLT/SPHERE instrument allow the identification of impact craters at their surfaces. Both crater diameter and cratering rates estimates are used to explain asteroid surface properties and as observational constraints on the origins of a few families
Experimental study of the Fe-Si-C system and application to carbon rich exoplanet by Francesca Miozzi Ferrini( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

Plus de 4000 exoplanètes ont été découvertes, orbitant autour d'étoiles ayant différentes compositions. Ces exoplanètes sont détectées et étudiées par observations indirectes qui, dans de nombreux cas, donnent accès aux propriétés principales des planètes: leurs masses et leurs rayons. Ces paramètres peuvent être calculés à partir d'un modèle et comparés à ceux observés. Toutefois, cela est plus difficile pour des planètes qui orbitent autour d'étoiles ayant une composition chimique différente du Soleil, par exemple enrichie en carbone, car les propriétés physiques des carbures (i.e. carbures de silicium ou de fer) sont inconnues. Dans cette étude les systèmes Si-C et Fe-Si-C ont été étudiés entre 20 et 200 GPa et 300-3000 K, en utilisant la diffraction de rayons x et l'analyse chimique des échantillons récupérés pour déterminer les propriétés physiques dans des conditions extrêmes. Dans le système Si-C les équations d'états et les modèles thermiques pour les deux phases de basse et haute pression ont été déterminés. Les résultats ont ensuite été utilisé pour calculer la relation masse-rayon de planètes synthétiques ayant un noyau de fer et un manteau de SiC. Concernant le système Fe-Si-C le diagramme de phase ternaire a été reconstruit. En faisant l'hypothèse d'une composition Fe-Si-C pour un noyau planétaire, quatre différentes séquences de cristallisation ont été démontrées, déterminant des comportements dynamiques très diffèrent. En conclusion la relation masse-rayon n'est pas suffisante pour déterminer la composition et la structure interne des exoplanètes observées mais des données relatives à la chimie du système planétaire sont requises
Préparation des futures missions in situ martiennes via la télédétection et l'expérimentation en spectroscopie de réflectance by Lucia Mandon( )

1 edition published in 2020 in French and held by 1 WorldCat member library worldwide

The exploration of Mars, which began in the 1960s, will soon be marked by a historic turning point, with the in situ investigation of two sites of Noachian age, the most primitive era of Mars. The selected landing sites, Jezero crater and Oxia Planum, exhibit from orbital data evidences for a hydrous past as well as good astrobiological potentials. The two rovers Perseverance and Rosalind Franklin (sent by the American and European-Russian agencies respectively) have a payload which includes the first visible and near-infrared (VNIR) reflectance spectrometers that will be used on the Martian surface, while this technique is the first to be used from orbit to assess and map the mineralogy of Mars. Our thesis is divided into two segments: first, an analysis of the two landing sites using remote sensing data was carried out, in order to characterize their geology and mineralogy. Second, terrestrial rocks similar to those on the landing sites were collected and analyzed using a reflectance spectrometer whose analysis beam is comparable in size to that of the VNIR channel of the SuperCam spectrometer onboard Perseverance. Our analysis on the Perseverance landing site allowed to examine the mineralogical variations of one of the most extensive geological units on the site, the olivine and carbonate unit. We suggest a pyroclastic origin for these deposits and date their emplacement at -3.82 +/- 0.07 Ga. This age will be useful to help calibrate the Martian chronology in the events of the Mars Sample Return mission. While Rosalind Franklin's landing site appears spectrally homogeneous from orbit, we show that there is textural, compositional, and mineralogical diversity at high resolution within the clays present at the site, which are the primary targets of the mission. During this thesis, we have produced a spectral database of samples analyzed in the laboratory. The reflectance spectra can be directly and automatically compared to those that will be measured in situ on rock outcrops. This database includes the first representative panel of Martian meteorites, natural magmatic rocks more or less altered and whose mineralogical compositions have been estimated, as well as synthetic mixtures of simplified composition and mineralogy that are directly comparable to those estimated on the landing sites. The reflectance spectra measured could be directly and automatically compared to future in situ measurements on Martian rock surfaces
Spectroscopies Raman et de luminescence résolues en temps pour l'exploration de Mars by Amaury Fau( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

In 2021, the NASA Mars 2020 rover will deploy the SuperCam instrument in the Jezero crater on Mars. This franco-american multi-tool instrument for remote analysis will be equiped with LIBS (chemical analysis) and with a time-resolved Raman and luminescence spectrometer (mineralogical analysis). After investigating various environmental parameters as well as intrinsic factors from the target sample, time-resolved Raman spectroscopy appears as a powerful tool to obtain high-quality Raman spectra free of parasitic signal (e.g. luminescence) for many mineral phases (carbonates, phosphates, silicates), even in the case of minerals hardly analysable with conventional Raman. A database of time-resolved Raman spectra has been elaborated. The effects of LIBS laser shots on the mineral structure and Raman fingerprint have been studied experimentally and through simple thermal modeling. Results show a major structural effect (vitrification and/or phase transition) in the case of opaque minerals with high optical absportion coefficient whereas the effects are minimal, or even non detectable, for more transparent and less absorbing minerals. Implications of these results for the operation of the Mars 2020 instruments are discussed. The study of Rare-Earth Elements (REE) luminescence in synthetic doped and natural apatites shows that luminescence is powerful to detect and characterize REEs. However, due to strong transfer energy among emission centers, the possible use of luminescence lifetime appears to be impossible to quantify REE in natural apatites
Étude de la composition et des propriétés physiques de surface de la comète 67P/Churyumov-Gerasimenko : interprétation des données VIRTIS/Rosetta etmesure en réflectance d'analogues cométaires by Batiste Rousseau( Book )

2 editions published in 2017 in French and held by 0 WorldCat member libraries worldwide

Lors de leur formation il y a 4,6 milliards d'années, les comètes ont intégré des matériaux transformés selon les conditions physiques et dynamiques du disque d'accrétion mais aussi une part de composés issus du milieu interstellaire. Parce qu'elles ont préservé leurs propriétés, étudier les comètes permet de mieux comprendre les conditions régnant dans le disque proto-planétaire entourant le jeune Soleil à une époque qui nous est inaccessible. Cela permet également de comprendre les différentes populations de comètes, leur processus de formation, leurs évolutions dynamiques, leur activité lorsqu'elles s'approchent du Soleil ou encore leur structure.La sonde européenne Rosetta a accompagné la comète 67P/Churyumov-Gerasimenko pendant deux ans. À son bord, une dizaine d'instruments ont permis d'étudier l'évolution de son activité, les gaz, la morphologie de surface ou les poussières parmi d'autres objectifs. VIRTIS est le spectromètre visible-infrarouge de Rosetta. Sa composante d'imagerie spectrale, VIRTIS-M, permet d'avoir accès à la dimension spatiale tout en bénéficiant d'une résolution spectrale modérée tandis que VIRTIS-H est un spectromètre ponctuel bénéficiant d'une plus grande résolution spectrale. Mon travail a reposé sur le traitement et l'analyse des données de ces instruments et se découpe en deux parties concentrées sur l'étude de la surface du noyau.La première est une analyse des paramètres spectraux et photométriques : albédo, pente spectrale, direction principale de la diffusion de la lumière par les particules, rugosité macroscopique. Dans une étude globale, j'ai mis en évidence les variations spatiales de certains de ces paramètres ; comparé les résultats issus de différents modèles ainsi que des deux instruments. J'ai ensuite déterminé localement ces paramètres, soulignant des différences selon le type de terrains ciblé. Ces études permettent de mieux comprendre les mécanismes liés à l'activité (dépôt/soulèvement de poussières, altération spatiale, variations de la teneur en glace) ou aux variations des propriétés de la surface (composition, texture).Le deuxième enjeu de cette thèse était de reproduire en laboratoire les observations réalisées par VIRTIS, et ce afin d'apporter des contraintes sur la composition et la texture de la surface. En collaboration avec l'IPAG de Grenoble j'ai donc mené des expériences consistant à produire des poudres très fines constituées de matériaux similaires à ceux que l'on suspecte d'être présents sur le noyau de 67P : matière organique (imitée par un charbon), silicates (olivine) et sulfures de fer (pyrite et pyrrhotite) sont ainsi tous observés dans les comètes ou leurs analogues. Je les ai ici broyés à des échelles micrométriques à nanométriques puis j'ai réalisé des mesures en réflectance dans la même gamme spectrale que VIRTIS. J'ai pu ainsi étudier les effets provoqués par les variations de la taille des grains, de la composition ou de la texture du mélange, mettant en avant des combinaisons reproduisant le spectre moyen de la comète. De manière générale, cette étude permet de mieux comprendre l'influence de matériaux rarement étudiés comme les sulfures de fer ainsi que le comportement spectral de poudres dont la taille des grains atteint un ordre de grandeur proche de celle de la longueur d'onde, ce qui est primordial dans l'étude des surfaces cométaires
Méthode d'analyse statistique appliquée au réseau d'observation européen des météores FRIPON by Simon Jeanne( )

1 edition published in 2020 in French and held by 0 WorldCat member libraries worldwide

The subject of this thesis is the observation of meteors using FRIPON, the French camera network. We discuss the whole chain of analysis of meteor measurements, from raw images to orbits. We developed a modified least squares estimator adapted to large and complex instruments such as a continental camera network. This modified least squares estimator is built to account for the multi-scale character of FRIPON: from the scale of individual cameras to the scale of this network covering Western Europe. It makes it possible to build a realistic estimator from measurements coming from cameras whose characteristics can be disparate, either because of the differences between the installation sites or of internal faults of certain cameras.The application of this estimator to meteor analysis is then discussed. In particular, we show that certain characteristics of meteor, such as the initial mass of the meteoroid or its enthalpy of destruction, cannot always be estimated from the study of their movement. An estimator of the least squares of these characteristics then does not make sense. We propose a new set of parameters allowing us to characterize a meteor and whose least squares estimators have an expectation and a variance that are always defined, whatever the type of meteor and the quality of the measurements.In addition, we study the various measurement biases that may arise during video observation of meteors. We show that the fastest meteors systematically present degenerate measurements. We show that these degenerations not only make it impossible to estimate certain characteristics, but also that they lead to an overestimation of the speed of entry of the meteoroids into the atmosphere. This overestimation of the speeds of the fastest meteors leads to the appearance of a population of falsely interstellar meteoroids. We show that, as part of the FRIPON network observation campaign, no meteoroid with an indubitable interstellar origin was observed. In fact, we question the existence of a large population of interstellar meteoroids that some teams claim to observe.If the recent discoveries of 1I/'Oumuamua and 2I/Borisov attest to the presence of bodies of interstellar origin within our Solar System and, therefore, potentially of meteoroids of interstellar origin which can impact the Earth, it is clear that few of these objects actually cross the path of our planet
 
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