PROXEMIA. Pintar la tensión de la proximidad

[EN] This project adresses the matter of the space’s tension between individuals, proxemic distances, occupancy and notion of territory, from the pictoric representation. In order to do this I have constantly used antropological and etological documentation, where animal behaviour related to the surrounding spaceand human conducts and its origins are approached, as well as cultural matters like the competitive game, where those issues underlie. Some of the books with which I have built the conceptual foundations of this research are The silent language and The hidden dimension, by Edward T. Hall, The naked ape, by Desmond Morris, and Homo Ludens, by Johan Huizinga, from which I have developed my pictoric production during more than a year, culminating in two series, Proxemia and Green Chairs, whith which I have executed a solo exhibition.[ES] Este proyecto aborda los temas de la tensión del espacio entre individuos, las distancias proxémicas, la ocupación y la noción de territorio desde la representación pictórica. Para ello constantemente me he valido de documentación antropológica y etológica con la que conformar los cimientos conceptuales, a partir de lo cual he desarrollado dos series pictóricas, con las que he realizado una exposición indiviidual.Cabedo Beltrán, V. (2018). PROXEMIA. Pintar la tensión de la proximidad. http://hdl.handle.net/10251/108170TFG

Accretion of water in carbonaceous chondrites: current evidence and implications for the delivery of water to early Earth

Protoplanetary disks are dust-rich structures around young stars. The crystalline and amorphous materials contained within these disks are variably thermally processed and accreted to make bodies of a wide range of sizes and compositions, depending on the heliocentric distance of formation. The chondritic meteorites are fragments of relatively small and undifferentiated bodies, and the minerals that they contain carry chemical signatures providing information about the early environment available for planetesimal formation. A current hot topic of debate is the delivery of volatiles to terrestrial planets, understanding that they were built from planetesimals formed under far more reducing conditions than the primordial carbonaceous chondritic bodies. In this review, we describe significant evidence for the accretion of ices and hydrated minerals in the outer protoplanetary disk. In that distant region highly porous and fragile carbon and water-rich transitional asteroids formed, being the parent bodies of the carbonaceous chondrites (CCs). CCs are undifferentiated meteorites that never melted but experienced other physical processes including thermal and aqueous alteration. Recent evidence indicates that few of them have escaped significant alteration, retaining unique features that can be interpreted as evidence of wet accretion. Some examples of carbonaceous chondrite parent body aqueous alteration will be presented. Finally, atomistic interpretations of the first steps leading to water-mediated alteration during the accretion of CCs are provided and discussed. From these new insights into the water retained in CCs we can decipher the pathways of delivery of volatiles to the terrestrial planets.Comment: 37 pages, 2 Tables, 10 Figures Presented in the International ESAC workshop "Ices in the Solar System" To be published in Space Science Reviews (SPAC-D-18-00036R3

Magnetically regulated collapse in the B335 protostar? II. Observational constraints on gas ionization and magnetic field coupling

Non-ideal magnetohydrodynamic effects that rule the coupling of the magnetic field to the circumstellar gas during the low-mass star formation process depend heavily on the local physical conditions, such as the ionization fraction of the gas. The purpose of this work is to observationally characterize the level of ionization of the circumstellar gas at small envelope radii and investigate its relation to the efficiency of the coupling between the star-forming gas and the magnetic field in the Class 0 protostar B335. We have obtained molecular line emission maps of B335 with ALMA, which we use to measure the deuteration fraction of the gas, its ionization fraction, and the cosmic-ray ionization rate, at envelope radii $\lesssim$1000 au. We find large fractions of ionized gas, $\chi_{e} \simeq 1-8 \times 10^{-6}$. Our observations also reveal an enhanced ionization that increases at small envelope radii, reaching values up to $\zeta_{CR} \simeq 10^{-14}$~s$^{-1}$ at a few hundred au from the central protostellar object. We show that this extreme ionization rate can be attributed to the presence of cosmic rays accelerated close to the protostar. We report the first resolved map of the cosmic-ray ionization rate at scales $\lesssim 1000$~au in a solar-type Class 0 protostar, finding remarkably high values. Our observations suggest that local acceleration of cosmic rays, and not the penetration of interstellar Galactic cosmic rays, may be responsible for the gas ionization in the inner envelope, potentially down to disk forming scales. If confirmed, our findings imply that protostellar disk properties may also be determined by local processes setting the coupling between the gas and the magnetic field, and not only by the amount of angular momentum available at large envelope scales and the magnetic field strength in protostellar cores.Comment: Submitted to A&A. Not yet referee

Study of erosion behaviour of conventional and nanostructured WC-12Co coatings sprayed by atmospheric plasma

Thermal sprayed WC-Co coatings are used extensively to enhance the wear resistance of a wide range of engineering components. In this paper, erosive resistance of plasma atmospheric sprayed WC-12Co coatings has been evaluated. Solid particle erosion tests were conducted on these coatings at different angles of impact with silica and alumina abrasives of size 250 µm. Coatings have been deposited by using micrometric and nanometric agglomerated powders, employing H2 and He as plasmogen gas. In order to determine the erosion regime (ductile or brittle), the influence of impact angle on the erosion rate has been studied. Optical microscope and FESEM have been used to analyze the eroded surface. The influence of the plasmogen gas and the powder employed on the erosive behaviour of the coating has been evaluated. An attempt to connect the erosive behaviour with mechanical properties and microstructure has been made. Hardness has been determined by means of several measurements of Vickers microhardness; fracture toughness has been estimated through indentation method. Identification of phases has been made by means of X Ray diffractio

Host plant scent mediates patterns of attraction/repellence among predatory mites

[EN] In mite communities, behavioral and foraging decisions of individuals rely on semiochemicals that they gather from the environment, which contain odors from plants, herbivores, and predators. Because herbivorous mites commonly co-occur with several species of phytoseiid predatory mites, which may engage in intraguild predation (IGP), predator mite decision-making relies on their ability to recognize odors signaling the presence of the herbivore but also that of potential competitors/predators. Here the odor-related foraging decisions of three predatory mites, Euseius stipulatus (Athias-Henriot), Neoseiulus californicus (McGregor) and Phytoseiulus persimilis (Athias-Henriot) (Mesostigmata: Phytoseiidae), which co-occur in citrus, compete for the herbivore Tetranychus urticae Koch (Prostigmata: Tetranychidae), and can engage in IGP were investigated. The composition of the volatile blends associated with the three predators was characterized. Moreover, the effect of these odors on the predators foraging decisions was measured. Results revealed that (1) the volatile signature of the three predatory mites is species specific, (2) the predators¿ foraging behavior is affected by heterospecific predator odors, and (3) predator responses strongly depend on the host plant: mutual attraction and mutual repellence occurred in Cleopatra mandarin and sour orange, respectively. These findings have important consequences for the management of systems where these species occur. The odor blends that make predators that share pest species as prey avoid each other could be used to improve pest control by minimizing undesired negative interactions among predator species, and by locally increasing predation risk on herbivore pest species.The authors thank M. Piquer (UJI) for technical assistance and J. Calvo (Koppert Biological Systems) for the supply of N. californicus and P. persimilis. This study was partially funded by the Spanish Research State Agency (research grants AGL2014-55616-C3, AGL2015-64990-2R, PID2019-103863RB-I00 and BES-2015-074570).Cruz-Miralles, J.; Cabedo-Lopez, M.; Guzzo, M.; Vacas, S.; Navarro-Llopis, V.; Ibáñez-Gual, MV.; Flors, V.... (2022). Host plant scent mediates patterns of attraction/repellence among predatory mites. Entomologia Generalis. 42(2):217-229. https://doi.org/10.1127/entomologia/2021/1237S21722942

Acute and long-term immune responses to SARS-CoV-2 infection in unvaccinated children and young adults with inborn errors of immunity

PurposeTo describe SARS-CoV-2 infection outcome in unvaccinated children and young adults with inborn errors of immunity (IEI) and to compare their specific acute and long-term immune responses with a sex-, age-, and severity-matched healthy population (HC).MethodsUnvaccinated IEI patients up to 22 years old infected with SARS-CoV-2 were recruited along with a cohort of HC. SARS-CoV-2 serology and ELISpot were performed in the acute phase of infection (up to 6 weeks) and at 3, 6, 9, and 12 months.ResultsTwenty-five IEI patients (median age 14.3 years, min.-max. range 4.5-22.8; 15/25 males; syndromic combined immunodeficiencies: 48.0%, antibody deficiencies: 16.0%) and 17 HC (median age 15.3 years, min.-max. range 5.4-20.0; 6/17 males, 35.3%) were included. Pneumonia occurred in 4/25 IEI patients. In the acute phase SARS-CoV-2 specific immunoglobulins were positive in all HC but in only half of IEI in whom it could be measured (n=17/25): IgG+ 58.8% (10/17) (p=0.009); IgM+ 41.2% (7/17)(p<0.001); IgA+ 52.9% (9/17)(p=0.003). Quantitative response (index) was also lower compared with HC: IgG IEI (3.1 ± 4.4) vs. HC (3.5 ± 1.5)(p=0.06); IgM IEI (1.9 ± 2.4) vs. HC (3.9 ± 2.4)(p=0.007); IgA IEI (3.3 ± 4.7) vs. HC (4.6 ± 2.5)(p=0.04). ELISpots positivity was qualitatively lower in IEI vs. HC (S-ELISpot IEI: 3/11, 27.3% vs. HC: 10/11, 90.9%; p=0.008; N-ELISpot IEI: 3/9, 33.3% vs. HC: 11/11, 100%; p=0.002) and also quantitatively lower (S-ELISpot IEI: mean index 3.2 ± 5.0 vs. HC 21.2 ± 17.0; p=0.001; N-ELISpot IEI: mean index 9.3 ± 16.6 vs. HC: 39.1 ± 23.7; p=0.004). As for long term response, SARS-CoV-2-IgM+ at 6 months was qualitatively lower in IEI(3/8, 37.5% vs. 9/10 HC: 90.0%; p=0.043), and quantitatively lower in all serologies IgG, M, and A (IEI n=9, 1.1 ± 0.9 vs. HC n=10, 2.1 ± 0.9, p=0.03; IEI n=9, 1.3 ± 1.5 vs. HC n=10, 2.9 ± 2.8, p=0.02; and IEI n=9, 0.6 ± 0.5 vs. HC n=10, 1.7 ± 0.8, p=0.002 –respectively) but there were no differences at remaining time points.ConclusionsOur IEI pediatric cohort had a higher COVID-19 pneumonia rate than the general age-range population, with lower humoral and cellular responses in the acute phase (even lower compared to the reported IEI serological response after SARS-CoV-2 vaccination), and weaker humoral responses at 6 months after infection compared with HC

Caractérisation des propriétés physico-chimiques du gaz formant une étoile : observations à haute résolution de la protoétoile de Classe 0 B335

The process of star formation is well known in a general aspect, however, a lot of details are still missing. Somequestions, such as the mode and efficiency of the accretion process or the role of the magnetic field, are still open andare key to completely understand star formation. The aim of this work is to put constraints on some of the physical andchemical processes happening in a young star forming core during the first stages of the collapse. For this purpose, weobtained high angular observations of the Class 0 protostellar object B335. This object, which is an isolated Bok Globule,is very well known as it is an excellent source to test theories of gravitational collapse during the low-mass starformation process. It has also been suggested as a good example of magnetically regulated collapse, as it presents astrongly pinched magnetic field morphology. Within the project, we obtained dust continuum and several molecularlines emission, probing scales from the envelope, around 4000 au, to the most inner part, at around 150 au, with theALMA interferometer. Our data set has probed to be very heterogeneous in nature as well as to present complex gaskinematics, observed in complex molecular line profiles. Within our observations of rare isotpologues from CO, weobserved double-peaked line profiles which could not be attributed to optically thin lines, as expected from theabundance of those molecules. We also studied the morphology of the line profiles at different offsets of the source, andfound that they were not in agreement with the expected models of symmetric spherical collapse. We use these facts tostudy the infall modes on the source and modeled the line profiles to obtain the main parameters, such as the peakvelocity, the velocity dispersion and the opacity. From this we found that the observed emission was optically thin, andthat each component of the double-peaked line profile had a linewidth typical from infall motions. This lead us topropose that the two peaks were coming from two different gas reservoirs with different kinematics, i.e. we propose thatthe collapse is not symmetric and it is occurring along the exterior of the cavity walls. Since the double-peaked profilesappeared in other CO derivatives, such as HCO+ and DCO+, we kept this hypothesis of the two distinct velocitycomponents to proceed with the derivation of the deuteration and the ionization fraction. Our values of the ionizationfraction show that B335 lies in the upper range of the values computed from the literature for protostellar objects. Sincewe resolve the maps of the ionization fraction, we can see different tendencies that point to different ionizationprocesses, i.e., ionization due to Cosmic Rays, probably enhanced due to the isolation of the object and the presence of anorganized magnetic field, and ionization due to accretion radiation close to the protostar. We also compare thedistribution of the ionization with the polarized dust emission, which is indicative of the morphology of the magneticfield. A good correlation is observed, where the largest values of the ionization fraction are correlated with thepolarized continuum intensity. We also attempted for the first time to compute the effect of ambipolar diffusion in aClass 0 object, i.e., difference in the kinematics of neutral and ionic molecules. We were able to observe that both type ofmolecules present different ranges of the velocity dispersion, which suggests that the ions are coupled to the magneticfield. In summary, a better view of the interplay between the gas and the magnetic field is obtained, suggesting a goodcoupling of the two and pointing to the fact that collapse in B335 is strongly magnetically regulatedLe processus de formation des étoiles est bien connu dans ses grand lignes, cependant, beaucoup de détails manquentencore. Certaines questions, telles que le mode et l'efficacité du processus d'accrétion ou le rôle du champ magnétique,restent ouvertes et sont essentielles pour bien comprendre le processus de formation des étoiles. Le but de ce travail estde poser des contraintes sur certains des processus physiques et chimiques qui se produisent dans un jeune coeurprotostellaire pendant les premières étapes de l'effondrement. Pur cela, nous avons obtenu des observations à hauterésolution angulaire de la protoètoile de Classe 0 B335. Cet objet, qui est un globule isolé, est très connu car c'est uneexcellente source pour tester les théories de l'effondrement gravitationnel au cours du processus de formation desétoiles de faible masse. C'est aussi un objet prototypique car considéré comme un bon exemple d'effondrement régulémagnétiquement, car il présente une morphologie de champ magnétique sous forme de sablier, évocateur d'un champfort étiré paru un potentiel gravitationel. Dans le cadre du projet, nous avons obtenu des observations de l'émissionthermique du continuum de poussière et plusieurs raies moléculaires, en sondant des échelles de l'enveloppe, autour de4000 au, jusqu'à la partie la plus interne, à environ 150 au, en utilisant l'interféromètre ALMA. Notre ensemble dedonnées s'est avéré être de nature très hétérogène et présenter une cinématique du gaz structurée, se traduisant par desprofiles complexes de raies moléculaires. Dans nos observations d'isotpologues rares du CO, nous avons observé desprofils de raies à double pic qui ne pouvaient pas être attribués à des raies optiquement minces, conformément a alafaible abondance de ces molécules. Nous avons également étudié la morphologie des profils de raies à différents échellesde l'enveloppe et avons constaté qu'ils n'étaient pas en accord avec les modèles attendus d'effondrement en symétriesphérique. Nous utilisons ces observations pour étudier la dynamique de l'effondrement sur la source et modéliser lesprofils de raies moléculaires pour obtenir les principaux paramètres, tels que la vitesse, la dispersion de vitesse etl'opacité. À partir de cela, nous avons constaté que l'émission observée était optiquement mince et que chaquecomposante du profil de raies à double pic avait une largeur de raie typique des vitesses d'effondrement. Cela nous aconduit à proposer que les deux pics provenaient de deux réservoirs de gaz différents avec une cinématique différente,c'est-à-dire que nous proposons que l'effondrement n'est pas symétrique et qu'il se produit le long de l'extérieur desparois de la cavité. Puisque les profils à double pic sont apparus dans d'autres dérivés du CO, tels que HCO+ et DCO+,nous avons gardé cette hypothèse des deux composantes de vitesse distinctes pour procéder à la dérivation de ladeutération et de la fraction d'ionisation. Nos valeurs de la fraction d'ionisation montrent que B335 se situe dans laplage supérieure des valeurs observées dans la littérature pour les objets protostellaires

Caractérisation des propriétés physico-chimiques du gaz formant une étoile : observations à haute résolution de la protoétoile de Classe 0 B335

The process of star formation is well known in a general aspect, however, a lot of details are still missing. Somequestions, such as the mode and efficiency of the accretion process or the role of the magnetic field, are still open andare key to completely understand star formation. The aim of this work is to put constraints on some of the physical andchemical processes happening in a young star forming core during the first stages of the collapse. For this purpose, weobtained high angular observations of the Class 0 protostellar object B335. This object, which is an isolated Bok Globule,is very well known as it is an excellent source to test theories of gravitational collapse during the low-mass starformation process. It has also been suggested as a good example of magnetically regulated collapse, as it presents astrongly pinched magnetic field morphology. Within the project, we obtained dust continuum and several molecularlines emission, probing scales from the envelope, around 4000 au, to the most inner part, at around 150 au, with theALMA interferometer. Our data set has probed to be very heterogeneous in nature as well as to present complex gaskinematics, observed in complex molecular line profiles. Within our observations of rare isotpologues from CO, weobserved double-peaked line profiles which could not be attributed to optically thin lines, as expected from theabundance of those molecules. We also studied the morphology of the line profiles at different offsets of the source, andfound that they were not in agreement with the expected models of symmetric spherical collapse. We use these facts tostudy the infall modes on the source and modeled the line profiles to obtain the main parameters, such as the peakvelocity, the velocity dispersion and the opacity. From this we found that the observed emission was optically thin, andthat each component of the double-peaked line profile had a linewidth typical from infall motions. This lead us topropose that the two peaks were coming from two different gas reservoirs with different kinematics, i.e. we propose thatthe collapse is not symmetric and it is occurring along the exterior of the cavity walls. Since the double-peaked profilesappeared in other CO derivatives, such as HCO+ and DCO+, we kept this hypothesis of the two distinct velocitycomponents to proceed with the derivation of the deuteration and the ionization fraction. Our values of the ionizationfraction show that B335 lies in the upper range of the values computed from the literature for protostellar objects. Sincewe resolve the maps of the ionization fraction, we can see different tendencies that point to different ionizationprocesses, i.e., ionization due to Cosmic Rays, probably enhanced due to the isolation of the object and the presence of anorganized magnetic field, and ionization due to accretion radiation close to the protostar. We also compare thedistribution of the ionization with the polarized dust emission, which is indicative of the morphology of the magneticfield. A good correlation is observed, where the largest values of the ionization fraction are correlated with thepolarized continuum intensity. We also attempted for the first time to compute the effect of ambipolar diffusion in aClass 0 object, i.e., difference in the kinematics of neutral and ionic molecules. We were able to observe that both type ofmolecules present different ranges of the velocity dispersion, which suggests that the ions are coupled to the magneticfield. In summary, a better view of the interplay between the gas and the magnetic field is obtained, suggesting a goodcoupling of the two and pointing to the fact that collapse in B335 is strongly magnetically regulatedLe processus de formation des étoiles est bien connu dans ses grand lignes, cependant, beaucoup de détails manquentencore. Certaines questions, telles que le mode et l'efficacité du processus d'accrétion ou le rôle du champ magnétique,restent ouvertes et sont essentielles pour bien comprendre le processus de formation des étoiles. Le but de ce travail estde poser des contraintes sur certains des processus physiques et chimiques qui se produisent dans un jeune coeurprotostellaire pendant les premières étapes de l'effondrement. Pur cela, nous avons obtenu des observations à hauterésolution angulaire de la protoètoile de Classe 0 B335. Cet objet, qui est un globule isolé, est très connu car c'est uneexcellente source pour tester les théories de l'effondrement gravitationnel au cours du processus de formation desétoiles de faible masse. C'est aussi un objet prototypique car considéré comme un bon exemple d'effondrement régulémagnétiquement, car il présente une morphologie de champ magnétique sous forme de sablier, évocateur d'un champfort étiré paru un potentiel gravitationel. Dans le cadre du projet, nous avons obtenu des observations de l'émissionthermique du continuum de poussière et plusieurs raies moléculaires, en sondant des échelles de l'enveloppe, autour de4000 au, jusqu'à la partie la plus interne, à environ 150 au, en utilisant l'interféromètre ALMA. Notre ensemble dedonnées s'est avéré être de nature très hétérogène et présenter une cinématique du gaz structurée, se traduisant par desprofiles complexes de raies moléculaires. Dans nos observations d'isotpologues rares du CO, nous avons observé desprofils de raies à double pic qui ne pouvaient pas être attribués à des raies optiquement minces, conformément a alafaible abondance de ces molécules. Nous avons également étudié la morphologie des profils de raies à différents échellesde l'enveloppe et avons constaté qu'ils n'étaient pas en accord avec les modèles attendus d'effondrement en symétriesphérique. Nous utilisons ces observations pour étudier la dynamique de l'effondrement sur la source et modéliser lesprofils de raies moléculaires pour obtenir les principaux paramètres, tels que la vitesse, la dispersion de vitesse etl'opacité. À partir de cela, nous avons constaté que l'émission observée était optiquement mince et que chaquecomposante du profil de raies à double pic avait une largeur de raie typique des vitesses d'effondrement. Cela nous aconduit à proposer que les deux pics provenaient de deux réservoirs de gaz différents avec une cinématique différente,c'est-à-dire que nous proposons que l'effondrement n'est pas symétrique et qu'il se produit le long de l'extérieur desparois de la cavité. Puisque les profils à double pic sont apparus dans d'autres dérivés du CO, tels que HCO+ et DCO+,nous avons gardé cette hypothèse des deux composantes de vitesse distinctes pour procéder à la dérivation de ladeutération et de la fraction d'ionisation. Nos valeurs de la fraction d'ionisation montrent que B335 se situe dans laplage supérieure des valeurs observées dans la littérature pour les objets protostellaires

Caractérisation des propriétés physico-chimiques du gaz formant une étoile : observations à haute résolution de la protoétoile de Classe 0 B335

The process of star formation is well known in a general aspect, however, a lot of details are still missing. Somequestions, such as the mode and efficiency of the accretion process or the role of the magnetic field, are still open andare key to completely understand star formation. The aim of this work is to put constraints on some of the physical andchemical processes happening in a young star forming core during the first stages of the collapse. For this purpose, weobtained high angular observations of the Class 0 protostellar object B335. This object, which is an isolated Bok Globule,is very well known as it is an excellent source to test theories of gravitational collapse during the low-mass starformation process. It has also been suggested as a good example of magnetically regulated collapse, as it presents astrongly pinched magnetic field morphology. Within the project, we obtained dust continuum and several molecularlines emission, probing scales from the envelope, around 4000 au, to the most inner part, at around 150 au, with theALMA interferometer. Our data set has probed to be very heterogeneous in nature as well as to present complex gaskinematics, observed in complex molecular line profiles. Within our observations of rare isotpologues from CO, weobserved double-peaked line profiles which could not be attributed to optically thin lines, as expected from theabundance of those molecules. We also studied the morphology of the line profiles at different offsets of the source, andfound that they were not in agreement with the expected models of symmetric spherical collapse. We use these facts tostudy the infall modes on the source and modeled the line profiles to obtain the main parameters, such as the peakvelocity, the velocity dispersion and the opacity. From this we found that the observed emission was optically thin, andthat each component of the double-peaked line profile had a linewidth typical from infall motions. This lead us topropose that the two peaks were coming from two different gas reservoirs with different kinematics, i.e. we propose thatthe collapse is not symmetric and it is occurring along the exterior of the cavity walls. Since the double-peaked profilesappeared in other CO derivatives, such as HCO+ and DCO+, we kept this hypothesis of the two distinct velocitycomponents to proceed with the derivation of the deuteration and the ionization fraction. Our values of the ionizationfraction show that B335 lies in the upper range of the values computed from the literature for protostellar objects. Sincewe resolve the maps of the ionization fraction, we can see different tendencies that point to different ionizationprocesses, i.e., ionization due to Cosmic Rays, probably enhanced due to the isolation of the object and the presence of anorganized magnetic field, and ionization due to accretion radiation close to the protostar. We also compare thedistribution of the ionization with the polarized dust emission, which is indicative of the morphology of the magneticfield. A good correlation is observed, where the largest values of the ionization fraction are correlated with thepolarized continuum intensity. We also attempted for the first time to compute the effect of ambipolar diffusion in aClass 0 object, i.e., difference in the kinematics of neutral and ionic molecules. We were able to observe that both type ofmolecules present different ranges of the velocity dispersion, which suggests that the ions are coupled to the magneticfield. In summary, a better view of the interplay between the gas and the magnetic field is obtained, suggesting a goodcoupling of the two and pointing to the fact that collapse in B335 is strongly magnetically regulatedLe processus de formation des étoiles est bien connu dans ses grand lignes, cependant, beaucoup de détails manquentencore. Certaines questions, telles que le mode et l'efficacité du processus d'accrétion ou le rôle du champ magnétique,restent ouvertes et sont essentielles pour bien comprendre le processus de formation des étoiles. Le but de ce travail estde poser des contraintes sur certains des processus physiques et chimiques qui se produisent dans un jeune coeurprotostellaire pendant les premières étapes de l'effondrement. Pur cela, nous avons obtenu des observations à hauterésolution angulaire de la protoètoile de Classe 0 B335. Cet objet, qui est un globule isolé, est très connu car c'est uneexcellente source pour tester les théories de l'effondrement gravitationnel au cours du processus de formation desétoiles de faible masse. C'est aussi un objet prototypique car considéré comme un bon exemple d'effondrement régulémagnétiquement, car il présente une morphologie de champ magnétique sous forme de sablier, évocateur d'un champfort étiré paru un potentiel gravitationel. Dans le cadre du projet, nous avons obtenu des observations de l'émissionthermique du continuum de poussière et plusieurs raies moléculaires, en sondant des échelles de l'enveloppe, autour de4000 au, jusqu'à la partie la plus interne, à environ 150 au, en utilisant l'interféromètre ALMA. Notre ensemble dedonnées s'est avéré être de nature très hétérogène et présenter une cinématique du gaz structurée, se traduisant par desprofiles complexes de raies moléculaires. Dans nos observations d'isotpologues rares du CO, nous avons observé desprofils de raies à double pic qui ne pouvaient pas être attribués à des raies optiquement minces, conformément a alafaible abondance de ces molécules. Nous avons également étudié la morphologie des profils de raies à différents échellesde l'enveloppe et avons constaté qu'ils n'étaient pas en accord avec les modèles attendus d'effondrement en symétriesphérique. Nous utilisons ces observations pour étudier la dynamique de l'effondrement sur la source et modéliser lesprofils de raies moléculaires pour obtenir les principaux paramètres, tels que la vitesse, la dispersion de vitesse etl'opacité. À partir de cela, nous avons constaté que l'émission observée était optiquement mince et que chaquecomposante du profil de raies à double pic avait une largeur de raie typique des vitesses d'effondrement. Cela nous aconduit à proposer que les deux pics provenaient de deux réservoirs de gaz différents avec une cinématique différente,c'est-à-dire que nous proposons que l'effondrement n'est pas symétrique et qu'il se produit le long de l'extérieur desparois de la cavité. Puisque les profils à double pic sont apparus dans d'autres dérivés du CO, tels que HCO+ et DCO+,nous avons gardé cette hypothèse des deux composantes de vitesse distinctes pour procéder à la dérivation de ladeutération et de la fraction d'ionisation. Nos valeurs de la fraction d'ionisation montrent que B335 se situe dans laplage supérieure des valeurs observées dans la littérature pour les objets protostellaires

Caractérisation des propriétés physico-chimiques du gaz formant une étoile : observations à haute résolution de la protoétoile de Classe 0 B335

Le processus de formation des étoiles est bien connu dans ses grand lignes, cependant, beaucoup de détails manquentencore. Certaines questions, telles que le mode et l'efficacité du processus d'accrétion ou le rôle du champ magnétique,restent ouvertes et sont essentielles pour bien comprendre le processus de formation des étoiles. Le but de ce travail estde poser des contraintes sur certains des processus physiques et chimiques qui se produisent dans un jeune coeurprotostellaire pendant les premières étapes de l'effondrement. Pur cela, nous avons obtenu des observations à hauterésolution angulaire de la protoètoile de Classe 0 B335. Cet objet, qui est un globule isolé, est très connu car c'est uneexcellente source pour tester les théories de l'effondrement gravitationnel au cours du processus de formation desétoiles de faible masse. C'est aussi un objet prototypique car considéré comme un bon exemple d'effondrement régulémagnétiquement, car il présente une morphologie de champ magnétique sous forme de sablier, évocateur d'un champfort étiré paru un potentiel gravitationel. Dans le cadre du projet, nous avons obtenu des observations de l'émissionthermique du continuum de poussière et plusieurs raies moléculaires, en sondant des échelles de l'enveloppe, autour de4000 au, jusqu'à la partie la plus interne, à environ 150 au, en utilisant l'interféromètre ALMA. Notre ensemble dedonnées s'est avéré être de nature très hétérogène et présenter une cinématique du gaz structurée, se traduisant par desprofiles complexes de raies moléculaires. Dans nos observations d'isotpologues rares du CO, nous avons observé desprofils de raies à double pic qui ne pouvaient pas être attribués à des raies optiquement minces, conformément a alafaible abondance de ces molécules. Nous avons également étudié la morphologie des profils de raies à différents échellesde l'enveloppe et avons constaté qu'ils n'étaient pas en accord avec les modèles attendus d'effondrement en symétriesphérique. Nous utilisons ces observations pour étudier la dynamique de l'effondrement sur la source et modéliser lesprofils de raies moléculaires pour obtenir les principaux paramètres, tels que la vitesse, la dispersion de vitesse etl'opacité. À partir de cela, nous avons constaté que l'émission observée était optiquement mince et que chaquecomposante du profil de raies à double pic avait une largeur de raie typique des vitesses d'effondrement. Cela nous aconduit à proposer que les deux pics provenaient de deux réservoirs de gaz différents avec une cinématique différente,c'est-à-dire que nous proposons que l'effondrement n'est pas symétrique et qu'il se produit le long de l'extérieur desparois de la cavité. Puisque les profils à double pic sont apparus dans d'autres dérivés du CO, tels que HCO+ et DCO+,nous avons gardé cette hypothèse des deux composantes de vitesse distinctes pour procéder à la dérivation de ladeutération et de la fraction d'ionisation. Nos valeurs de la fraction d'ionisation montrent que B335 se situe dans laplage supérieure des valeurs observées dans la littérature pour les objets protostellaires.The process of star formation is well known in a general aspect, however, a lot of details are still missing. Somequestions, such as the mode and efficiency of the accretion process or the role of the magnetic field, are still open andare key to completely understand star formation. The aim of this work is to put constraints on some of the physical andchemical processes happening in a young star forming core during the first stages of the collapse. For this purpose, weobtained high angular observations of the Class 0 protostellar object B335. This object, which is an isolated Bok Globule,is very well known as it is an excellent source to test theories of gravitational collapse during the low-mass starformation process. It has also been suggested as a good example of magnetically regulated collapse, as it presents astrongly pinched magnetic field morphology. Within the project, we obtained dust continuum and several molecularlines emission, probing scales from the envelope, around 4000 au, to the most inner part, at around 150 au, with theALMA interferometer. Our data set has probed to be very heterogeneous in nature as well as to present complex gaskinematics, observed in complex molecular line profiles. Within our observations of rare isotpologues from CO, weobserved double-peaked line profiles which could not be attributed to optically thin lines, as expected from theabundance of those molecules. We also studied the morphology of the line profiles at different offsets of the source, andfound that they were not in agreement with the expected models of symmetric spherical collapse. We use these facts tostudy the infall modes on the source and modeled the line profiles to obtain the main parameters, such as the peakvelocity, the velocity dispersion and the opacity. From this we found that the observed emission was optically thin, andthat each component of the double-peaked line profile had a linewidth typical from infall motions. This lead us topropose that the two peaks were coming from two different gas reservoirs with different kinematics, i.e. we propose thatthe collapse is not symmetric and it is occurring along the exterior of the cavity walls. Since the double-peaked profilesappeared in other CO derivatives, such as HCO+ and DCO+, we kept this hypothesis of the two distinct velocitycomponents to proceed with the derivation of the deuteration and the ionization fraction. Our values of the ionizationfraction show that B335 lies in the upper range of the values computed from the literature for protostellar objects. Sincewe resolve the maps of the ionization fraction, we can see different tendencies that point to different ionizationprocesses, i.e., ionization due to Cosmic Rays, probably enhanced due to the isolation of the object and the presence of anorganized magnetic field, and ionization due to accretion radiation close to the protostar. We also compare thedistribution of the ionization with the polarized dust emission, which is indicative of the morphology of the magneticfield. A good correlation is observed, where the largest values of the ionization fraction are correlated with thepolarized continuum intensity. We also attempted for the first time to compute the effect of ambipolar diffusion in aClass 0 object, i.e., difference in the kinematics of neutral and ionic molecules. We were able to observe that both type ofmolecules present different ranges of the velocity dispersion, which suggests that the ions are coupled to the magneticfield. In summary, a better view of the interplay between the gas and the magnetic field is obtained, suggesting a goodcoupling of the two and pointing to the fact that collapse in B335 is strongly magnetically regulate