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Les Etoiles Massives Associees Aux Regions Hii Compactes Des Nuages De Magellan
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Book Synopsis Les étoiles massives associées aux régions HII compactes des nuages de Magellan by : Romain Selier
Download or read book Les étoiles massives associées aux régions HII compactes des nuages de Magellan written by Romain Selier and published by . This book was released on 2012 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is devoted to compact HII regions in the Magellanic Clouds. The study is more specifically focused on a rare class of HII regions : the High-Excitation Blobs (HEBs). These objects are interesting because of the stellar population associated, newborn massive stars. This feature is essential in the context of the massive star formation in Magellanic Clouds. The studies carried out during this thesis have improved our understanding of these objects by significantly increasing the number of known HEBs. This work is based on the multi-wavelengths analysis of the HII regions using high angular resolution observations (HST, NTT, Spitzer). First, we have studied the youngest massive stars. We have determined the presence of a HEB in N66, the most spectacular HII region of the Small Magellanic Cloud. The study shows that this region probably represents the youngest event of massive star formation in the whole nebular complex. Subsequently, we discuss the topic actively debated of isolated massive star formation. In this context, we present the case of an isolated HII region, located away from any stellar concentration. Moreover, the analysis of this region shows that it contains a massive star which makes this region one of the best known candidates of massive star formed in isolation. Finally, we are interested in compact HII regions at the outskirts of the Magellanic Clouds. We present here the comparative analysis of the physical properties of these regions
Book Synopsis EVOLUTION CHIMIQUE DES NUAGES DE MAGELLAN by : Vanessa Hill
Download or read book EVOLUTION CHIMIQUE DES NUAGES DE MAGELLAN written by Vanessa Hill and published by . This book was released on 1997 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE THESE EST CONSACREE A L'ETUDE DE L'EVOLUTION CHIMIQUE DES NUAGES DE MAGELLAN (NMS), A TRAVERS, D'UNE PART, L'ETUDE DETAILLEE DES ABONDANCES D'UN ECHANTILLON DE NEUF ETOILES SUPERGEANTES DE TYPE F DU GRAND NUAGE DE MAGELLAN (GNM), ET UN AUTRE DE SIX SUPERGEANTES FROIDES (DE TYPE K) DU PETIT NUAGE DE MAGELLAN (PNM). PARMI LES RESULTATS OBTENUS, ON PEUT MENTIONNER LES SUIVANTS : 1- AUCUN GRADIENT D'ABONDANCE N'EST OBSERVE, NI DANS LE GNM, NI DANS LE PNM. 2- L'ANALYSE DES ELEMENTS C ET N LAISSE APPARAITRE LA REMONTEE EN SURFACE, DES PRODUITS DU CYCLE CNO, CE QUI EST CONFIRME PAR LE RAPPORT ISOTOPIQUE DU CARBONE (MESURE POUR LA PREMIERE FOIS DANS LE PNM). 3- L'ABONDANCE DU LITHIUM EST VARIABLE, SUGGERANT UNE EFFICACITE VARIABLE DES PROCESSUS DE MELANGE. 4- LE RAPPORT O/FE EST ANALOGUE DANS LE PNM, LE GNM ET LES SUPERGEANTES DE LA GALAXIE, L'EXPLICATION LA PLUS SIMPLE ETANT UNE EVOLUTION PARALLELE DES TROIS GALAXIES, AVEC UNE ACTIVITE PLUS FAIBLE DE FORMATION D'ETOILES DANS LES NMS. 5- L'ABONDANCE DE C ET DE N ET LE RAPPORT C/O DANS LES SUPERGEANTES SEMBLE DIFFERENTE DE CEUX TROUVES DANS LES REGIONS H II. 6- LE RAPPORT DES ELEMENTS TRES LOURDS (ISSUS DES PROCESSUS S- ET R- : LA, EU) AUX ELEMENTS LOURDS (Y, SR), EST SUPERIEUR A CELUI OBSERVE LA GALAXIE. D'AUTRE PART, NOUS AVONS MONTRE COMMENT L'ETUDE DES ABONDANCES D'UNE POPULATION PLUS VIEILLE DANS LES NUAGES DE MAGELLAN POURRAIT LEVER DES INCERTITUDES SUR LES PROCESSUS DE FORMATION D'ETOILES (FORMATION CONTINUE OU PAR EPISODES DE BURSTS SUCCESSIFS). DANS CETTE OPTIQUE, NOUS TENTONS UNE APPROCHE DE LA POPULATION VIEILLE (POP II) DU GNM, A TRAVERS L'ETUDE D'UN ECHANTILLON DE PLUSIEURS MILLIERS D'ETOILES VARIABLES RR LYRAE DETECTEES PAR EROS (UNE RECENTE EXPERIENCE DE RECHERCHE DE MATIERE NOIRE PAR EFFET DE MICROLENTILLE GRAVITATIONNELLE). NOUS AVONS PU MONTRER, PAR EXEMPLE, QUE LA METALLICITE MOYENNE DE CETTE POPULATION, BOULEVERSE LES IDEES CONCERNANT LA FORMATION D'ETOILES DANS LE GNM.
Book Synopsis ETUDE DES ETOILES DU TYPE WOLF-RAYET DANS LES NUAGES DE MAGELLAN by : Jacques Breysacher
Download or read book ETUDE DES ETOILES DU TYPE WOLF-RAYET DANS LES NUAGES DE MAGELLAN written by Jacques Breysacher and published by . This book was released on 1988 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: ANALYSE DETAILLEE DE 118 ETOILES DE TYPE WOLF RAYET APPARTENANT AUX NUAGES DE MAGELLAN (DONT 8 SEULEMENT DANS LE PETIT NUAGE); LEUR REPARTITION DANS LES ASSOCIATIONS STELLAIRES OB ET LES REGIONS HII EST EXEMINEE, DE MEME QUE LA FREQUENCE DES SYSTEMES BINAIRES DE TYPE WR. LA DISTRIBUTION PARMI LES DIFFERENTES CLASSES SPECTRALES DES SEQUENCES WN ET WC EST ETUDIEE. UNE NOUVELLE CALIBRATION DE LA MAGNITUDE ABSOLUE DES ETOILES DE TYPE WOLF RAYET EST PROPOSEE ET UN MODELE D'EVOLUTION STELLAIRE PRESENTE
Download or read book La voie lactée written by James Lequeux and published by EDP Sciences. This book was released on 2023-08-02T00:00:00+02:00 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Notre connaissance de la Voie lactée a été profondément renouvelée depuis une dizaine d’années suite aux résultats du satellite astrométrique HIPPARCOS et aux grands relevés stellaires. Bien des concepts que l’on croyait bien établis se sont effondrés, pour être remplacés par d’autres qui vont dans le sens d’une plus grande complexité : en particulier, la mise en évidence des migrations radiales des étoiles vient brouiller l’image simpliste que l’on avait du disque galactique. Certains sujets ont fait d’énormes progrès, par exemple la physique du centre de la Voie lactée avec son trou noir massif, mais d’autres problèmes subsistent, comme la nature de la matière noire qui semble exister dans notre Galaxie. Cet ouvrage fait le point des connaissances actuelles sur la Voie lactée, présentées d’une manière aussi simple et didactique que possible. Les notions de base sont toujours rappelées, ce qui rend son accès possible aux lecteurs n’ayant pas de formation approfondie en astronomie. Cet ouvrage de base servira pour mieux comprendre les résultats attendus de Gaia, qui vont arriver dans quelques années après le lancement en 2013. Françoise Combes est astronome à l’Observatoire de Paris et membre de l’Académie des sciences. Son activité couvre une très grande partie des sujets abordés dans ce livre, avec une prédilection pour les simulations numériques. James Lequeux est astronome émérite à l’Observatoire de Paris. Ses principales spécialités sont le milieu interstellaire, la formation des étoiles et l’évolution des galaxies.
Book Synopsis Etoiles massives les plus jeunes des nuages de Magellan by : Frédéric Meynadier
Download or read book Etoiles massives les plus jeunes des nuages de Magellan written by Frédéric Meynadier and published by . This book was released on 2005 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evolution des grandes nébuleuses le long de la Barre du Grand Nuage de Magellan by : Patricia Ambrocio-Cruz
Download or read book Evolution des grandes nébuleuses le long de la Barre du Grand Nuage de Magellan written by Patricia Ambrocio-Cruz and published by . This book was released on 1999 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE THESE PRESENTE L'ETUDE DE NEBULEUSES IONISEES DU GRAND NUAGE DE MAGELLAN (GNM), DANS UNE AIRE OU LES PHOTOGRAPHIES UV MONTRENT DES ASSOCIATIONS OB S'ALIGNANT LE LONG DE LA BARRE STELLAIRE, ET VERS LE NORD-OUEST SUR PLUS DE 3.5 KPC. LEUR ALIGNEMENT A SUGGERE UN BRAS SPIRAL ET UNE ONDE SE PROPAGEANT. CET EMPLACEMENT COINCIDE AVEC UNE AIRE DU GNM DANS LAQUELLE DEUX COUCHES D'HYDROGENE NEUTRE SONT OBSERVEES. PAR L'ETUDE CINEMATIQUE ET DYNAMIQUE DES NEBULEUSES RELIEES AUX ASSOCIATIONS OB, IL EST POSSIBLE DE SITUER CES DIFFERENTES ENTITES, PAR RAPPORT AU GAZ NEUTRE, ET PAR RAPPORT A UNE ONDE EVENTUELLE STIMULANT LA FORMATION STELLAIRE AU VOISINAGE DE LA BARRE DU GNM. ON A DONC EFFECTUE UNE ETUDE DETAILLEE DE LA CINEMATIQUE DES NEBULEUSES, AFIN DE DISTINGUER LES MOUVEMENTS SYSTEMIQUES DES MOUVEMENTS IMPULSES PAR LES ETOILES EXCITATRICES. LES OBSERVATIONS UTILISEES SONT DES OBSERVATIONS 3-D, OBTENUES AVEC UN INTERFEROMETRE A BALAYAGE. POUR LES NEBULEUSES DE TAILLE DE 100-200 PC MONTRANT DES EFFETS D'EVOLUTION, IL A FALLU, POUR LES COMPRENDRE, ETUDIER LES DETAILS DE LEUR CHAMP CINEMATIQUE ET RETRACER LEUR EVOLUTION. LA METHODE UTILISEE EST D'ETABLIR LE BILAN ENERGETIQUE EN COMPARANT L'ENERGIE OBSERVEE DANS LES BULLES ENTOURANT LES ETOILES MASSIVES, ET L'ENERGIE INJECTEE PAR CES ETOILES DU FAIT DE LEURS VENTS STELLAIRES. POUR CERNER LES RELATIONS D'EVOLUTION ENTRE LES GRANDES REGIONS HII OBSERVEES ET LEURS ETOILES EXCITATRICES, IL A ETE NECESSAIRE DE MODELISER LES NEBULEUSES PAR DES SIMULATIONS FAISANT EVOLUER LES REGIONS HII DANS UN MILIEU A FORT GRADIENT DE DENSITE. CONNAISSANT LES DIFFERENTES CAUSES DES MOUVEMENTS D'EXPANSION DETECTES, IL EST FINALEMENT POSSIBLE DE DEGAGER LA STRUCTURE ET LES EFFETS SUPPLEMENTAIRES, PROVENANT D'AUTRES PHENOMENES.
Book Synopsis EVOLUTION CHIMIQUE DES NUAGES DE MAGELLAN PAR L'ETUDE DES NEBULEUSES GAZEUSES by : PIERRE.. LEISY
Download or read book EVOLUTION CHIMIQUE DES NUAGES DE MAGELLAN PAR L'ETUDE DES NEBULEUSES GAZEUSES written by PIERRE.. LEISY and published by . This book was released on 1995 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES NEBULEUSES PLANETAIRES (NP) GALACTIQUES SOUFFRENT DRAMATIQUEMENT DE NOTRE IMPOSSIBILITE A CALCULER PRECISEMENT LEURS DISTANCES. LES DISTANCES DU PETIT ET DU GRAND NUAGE DE MAGELLAN SONT QUANT A ELLES BIEN DETERMINEES. PAR SUITE, ON CONNAIT MIEUX LEURS PROPRIETES PHYSIQUES: LES MASSES ET LES LUMINOSITES DES NP, FORTEMENT DEPENDANTES DE LA DISTANCE, SONT DES PARAMETRES INDISPENSABLES A LA DETERMINATION DU TAUX DE PRODUCTION DES ELEMENTS CHIMIQUES. EN PLUS DES SPECTRES MIS A MA DISPOSITION, J'AI OBSERVE SUR PLUSIEURS TELESCOPES OPTIQUES DE L'ESO, ET J'AI AUSSI PREPARE ET EFFECTUE 2 MISSIONS POUR OBSERVER PLUSIEURS DE NOS OBJETS AVEC LE SATELLITE ULTRAVIOLET IUE. J'AI ENSUITE REDUIT TOUS CES SPECTRES ET GRACE A LEUR TRES BONNE QUALITE, UNE DETERMINATION PRECISE DES ABONDANCES A PU ETRE MENEE A BIEN. UNE COMPARAISON AVEC LES DETERMINATIONS DES NP EN COMMUN A AUSSI ETE FAITE, AINSI QU'UNE REANALYSE DE L'ENSEMBLE DES DONNEES DES OBJETS DEJA PUBLIES, AFIN DE CALCULER LES ABONDANCES DE MANIERE HOMOGENE, SUR UN ECHANTILLON REPRESENTATIF. LES NP NOUS RENSEIGNENT SUR LES ABONDANCES EXISTANT AU MOMENT DE LA FORMATION DE L'ETOILE PROGENITRICE. ON LES COMPARE ENSUITE AUX ABONDANCES ACTUELLES (DETERMINEES DANS LES REGIONS HII). LES NP SONT ISSUES D'ETOILES DE MASSES INTERMEDIAIRES, ET ELLES FABRIQUENT DANS LEUR CUR, PENDANT LEUR EVOLUTION, DES ELEMENTS LEGERS (HE, C, N). LES PRODUITS DES REACTIONS NUCLEAIRES SONT MELANGES ET APPARAISSENT DANS LES ENVELOPPES GAZEUSES DES NP. TOUTES CES DONNEES PERMETTENT DE MIEUX CONTRAINDRE LES MODELES D'EVOLUTION STELLAIRE OU D'ENRICHISSEMENT CHIMIQUE DU MILIEU INTERSTELLAIRE PAR LES ETOILES DE MASSES INTERMEDIAIRES. IL EST AUSSI POSSIBLE DE RETRACER L'EVOLUTION CHIMIQUE DE CES 2 GALAXIES IRREGULIERES A FAIBLE METALLICITE
Book Synopsis Etude des complexes region HII-nuages moléculaires dans la galaxie et dans le grand nuage de Magellan by : Mohamed Heydari-Malayeri
Download or read book Etude des complexes region HII-nuages moléculaires dans la galaxie et dans le grand nuage de Magellan written by Mohamed Heydari-Malayeri and published by . This book was released on 1983 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evolution photométrique de notre galaxie et des nuages de Magellan by : Elisabeth Vangioni-Flam
Download or read book Evolution photométrique de notre galaxie et des nuages de Magellan written by Elisabeth Vangioni-Flam and published by . This book was released on 1980 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: ON PRESENTE L'ETUDE DES COULEURS DU VOISINAGE SOLAIRE A L'AIDE D'UN MODELE D'EVOLUTION GALACTIQUE QUI PERMET D'ETUDIER UN SITE ASTROPHYSIQUE EN TERMES DE TAUX DE FORMATION D'ETOILES EN FONCTION DU TEMPS ET DE LA FONCTION DE MASSE INITIALE. ON SE CONSACRE ENSUITE A UNE ETUDE DE LA REGION A 5 KPC DU CENTRE GALACTIQUE A L'AIDE DU MODELE D'EVOLUTION. LES OBSERVATIONS DE CETTE REGION A DIFFERENTES LONGUEURS D'ONDE REVELENT UNE GRANDE ACTIVITE DE FORMATION STELLAIRE. ON UTILISE LES OBSERVATIONS DANS L'UV LOINTAIN POUR ETUDIER LES POPULATIONS D'ETOILES MASSIVES DES NUAGES DE MAGELLAN. LA CONCLUSION FAIT LA SYNTHESE DES RESULTATS OBTENUS ET TENTE DE LES INSERER DANS LE CADRE GENERAL DE L'EVOLUTION GALACTIQUE
Book Synopsis Updates in Volcanology by : Karoly Nemeth
Download or read book Updates in Volcanology written by Karoly Nemeth and published by BoD – Books on Demand. This book was released on 2016-09-21 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Updates in Volcanology - From Volcano Modeling to Volcano Geology is a new book that is based on book chapters offered by various authors to provide a snapshot of current trends in volcanological researches. Following a short Introduction, the book consists of three sections, namely, ''Understanding the Volcano System from Petrology, Geophysics to Large Scale Experiments,'' ''Volcanic Eruptions and Their Impact to the Environment,' and ''Volcanism in the Geological Record.'' These sections collect a total of 13 book chapters demonstrating clearly the research activity in volcanology from geophysical aspects of volcanic systems to their geological framework. Each chapter provides a comprehensive summary of their subject's current research directions. This book hence can equally be useful for students and researchers.
Book Synopsis The X-ray Universe by : Wallace H. Tucker
Download or read book The X-ray Universe written by Wallace H. Tucker and published by . This book was released on 1985 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beyond the range of optical perception--and of ordinary imaginings--a new and violent universe lay undetected until the advent of space exploration. Supernovae, black holes, quasars and pulsars--these were the secrets of the highenergy world revealed when, for the first time, astronomers attached their instruments to rockets and lofted them beyond the earth's x-ray-absorbing atmosphere. The X-Ray Universe is the story of these explorations and the fantastic new science they brought into being. It is a first-hand account: Riccardo Giacconi is one of the principal pioneers of the field, and Wallace Tucker is a theorist who worked closely with him at many critical periods. The book carries the reader from the early days of the Naval Research Laboratory through the era of V-2 rocketry, Sputnik, and the birth of NASA, to the launching of the Einstein X-Ray Observatory. But this is by no means just a history. Behind the suspenseful, sometimes humorous details of human personality grappling with high technology lies a sophisticated exposition of current cosmology and astrophysics, from the rise and fall of the steady-state theory to the search for the missing mass of the universe.
Book Synopsis Astrophysical Masers (IAU S336) by : International Astronomical Union. Symposium
Download or read book Astrophysical Masers (IAU S336) written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2018-09-13 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizes state of the art observations and theories pertaining to astrophysical masers and their environments, for graduate students and researchers.
Book Synopsis Formation and Evolution of Galaxy Outskirts (IAU S321) by : Armando Gil de Paz
Download or read book Formation and Evolution of Galaxy Outskirts (IAU S321) written by Armando Gil de Paz and published by Cambridge University Press. This book was released on 2017-02-28 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The borders between galaxies and the almost empty intergalactic medium are ill-defined regions where gas struggles to form stars. The proceedings of IAU Symposium 321 summarize our current understanding of the rarefied universe and prepare for the optimal exploitation of upcoming astronomical instruments. They discuss the most recent advances in the study of the stellar, dust and gas content of galaxy outskirts, going from resolved stellar populations in the Milky Way and in the Local Group to the study of high-redshift systems. Such a broad approach, both in terms of galaxy components and evolutionary epochs, is necessary to take full advantage of the recent discoveries made by facilities at all wavelengths, to deepen our knowledge of the assembly and evolution of these elusive regions and to establish their role within the evolution of galaxies as a whole and their interactions with the surrounding intergalactic medium.
Download or read book Appity Slap written by and published by Erika Blanchard. This book was released on with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Spectral Energy Distribution of Galaxies - SED 2011 (IAU S284) by : Richard J. Tuffs
Download or read book The Spectral Energy Distribution of Galaxies - SED 2011 (IAU S284) written by Richard J. Tuffs and published by Cambridge University Press. This book was released on 2012-08-30 with total page 533 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent observational developments are providing the first truly panchromatic view of galaxies, extending from the radio to TeV gamma-rays. This is motivating the development of new models for the interpretation of spectral energy distributions (SEDs) of galaxies in terms of the formation, evolution and emission of stellar and accretion-driven sources of photons, the interaction of the photons with the gaseous and dust components of the interstellar medium, and high-energy processes involving cosmic rays. IAU Symposium 284 details progress in the development of such models, their relation to fundamental theory, and their application to the interpretation of the panchromatic emission from the Milky Way and nearby galaxies, connecting the latter with models for the evolution of the SEDs of distant galaxies, and the extragalactic background light. IAU S284 is a useful resource for all researchers working with the copious amounts of multiwavelength data for galaxies now becoming available.
Book Synopsis The Galactic Interstellar Medium by : W.B. Burton
Download or read book The Galactic Interstellar Medium written by W.B. Burton and published by Springer Science & Business Media. This book was released on 2006-04-18 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: The previous Saas-Fee Advanced Course dedicated to the interstellar medium took place in 1972. The tremendous scientific advances that have occurred in this field since then, in particular owing to the availabihty of receivers working at completely unexplored wavelength bands, fuUy justified a new set of lectures. As a consequence, the members of the Swiss Society for Astrophysics and As tronomy voted that "The Galactic Interstellar Medium" should be the subject of the 1991 course. The 21st Saas Fee Advanced Course took place in Les Diablerets from 18 to 23 March 1991, gathering together about 80 participants from all over the world, but mostly from Europe. According to a rule that has proved to lead to success, but also to chal lenge the lecturers' energy, the format of a Saas-Fee Advanced Course consists traditionally of 28 lectures of 45 minutes which take place in the morning and late afternoon, leaving ample time for discussions, self-study, hiking or skiing. Despite the inordinate work load imposed, this year's lecturers felt that the subject was sufficiently dense to increase the lecture time by 1/3! This proved judicious and left more time for questions and discussions during the lectures.
Book Synopsis The Interstellar Medium by : K. Pinkau
Download or read book The Interstellar Medium written by K. Pinkau and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years it has become apparent that con tributions to our knowledge about the interstellar medium are made by practically all forms of astronomy ranging from radio- to gamma ray observations, and from cosmic ray measurements. It was thus thought fruitful to arrange for an interdisciplinary meeting of astron omers from the various fields of investigation, and of high energy astrophysicists. This meeting took place at Schliersee (Bavaria) from April 2 to 13, 1973. Lectures and some of the discussions held during that Advanced Study Institute are reproduced here. unfortunately, no manuscripts of the two lectures about infrared and cosmic ray observations were re ceived and these are thus not available here. However, it was thought to be more important to proceed now with the publication. The organisers are very grateful to Miss H. Eichele for her technical help during the meeting. The or ganisation of the Institute and the publication of the proceedings would have been impossible without the very great efforts and help of Mrs. M. Brunner and Mrs. D.Preis. I would also like to express my gratitude to my col leagues K.W. Michel and S. Drapatz for their many con tributions towards the success of the meeting.
