Download or read book Abundance Anomalies in Globular Clusters in Light of Models of Rotating Stars written by Thibaut Decressin and published by . This book was released on 2007 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abundance Anomalies in Globular Clusters in Light of Models of Rotaring Stars written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: L'objet de cette thèse est de déterminer l'origine des importantes variations d'abondances en éléments légers observées d'étoile à étoile dans les globulaires galactiques qui sont des amas stellaires denses gravitationnellement liés comptant parmi les plus vieux objets de l'Univers. Ce travail présente l'étude des effets de la rotation dans les modèles théoriques d'étoiles en vue de mieux comprendre ces anomalies. Dans un premier temps, nous avons montré que les étoiles de masse intermédiaire en rotation ne peuvent être à l'origine de ces anomalies. Nous avons ensuite étudié les effets de la rotation rapide sur des étoiles massives ; ceci nous a conduits à élaborer le scénario du vent des étoiles massives en rotation rapide pour expliquer les observations par une pollution du milieu intra-amas où sont nées les étoiles chimiquement anormales. Enfin, des contraintes sur la formation des amas globulaires ont été dégagées.
Download or read book Abundance Anomalies in Globular Clusters in Light of Models of Rotaring Stars written by Thibaut Decressin and published by . This book was released on 2007 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'objet de cette thèse est de déterminer l'origine des importantes variations d'abondances en éléments légers observées d'étoile à étoile dans les globulaires galactiques qui sont des amas stellaires denses gravitationnellement liés comptant parmi les plus vieux objets de l'Univers. Ce travail présente l'étude des effets de la rotation dans les modèles théoriques d'étoiles en vue de mieux comprendre ces anomalies. Dans un premier temps, nous avons montré que les étoiles de masse intermédiaire en rotation ne peuvent être à l'origine de ces anomalies. Nous avons ensuite étudié les effets de la rotation rapide sur des étoiles massives ; ceci nous a conduits à élaborer le scénario du vent des étoiles massives en rotation rapide pour expliquer les observations par une pollution du milieu intra-amas où sont nées les étoiles chimiquement anormales. Enfin, des contraintes sur la formation des amas globulaires ont été dégagées.
Download or read book Globular Clusters written by C. Martinez Roger and published by Cambridge University Press. This book was released on 1999-10-28 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: An accessible introduction to globular clusters for graduate students, and a comprehensive and up-to-date reference for researchers.
Download or read book Deep Mixing in Globular cluster Red Giants written by P. A. Denissenkov and published by Cambridge Scientific Publishers. This book was released on 2004 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents and reviews the results of studies on subjects closely related to the problems of abundance anomalies in globular clusters and covers in particular the problem of deep mixing in globular-cluster red giants and describes a diffusion model and a mechanism for extra mixing in red giants. The author traces the development of scenarios to explain the origin of star-to star variations in elemental abundances in globular clusters: primordial nucleosynthesis and mixing and the background to the proposal of a combined scenario and a model for the chemical evolution of globular clusters. This review provides a useful reference text for graduates and researchers in astrophysics.
Download or read book Abundance Anomalies in Globular Cluster Red Giant Stars written by Benedict Bryan Messenger and published by . This book was released on 2000 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Elements in the Universe IAU S268 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2010-05-13 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: IAU Symposium 268 presents an overview of the most recent observational and theoretical research on the formation and evolution of light elements in the Universe: H, He, Li, Be, B, and their isotopes. Astrophysicists from a variety of subfields discuss recent developments that will improve our understanding of the light elements and provide important clues to stellar and galactic evolution, Big Bang nucleosynthesis, and cosmology. Striking observational progress has been achieved recently through the advent of next generation ground- and space-based telescopes, such as the cosmic microwave background experiments that allow the accurate determination of the baryon density of the Universe. New theoretical breakthroughs in describing stellar interiors and the chemical evolution of complex systems and the remaining challenges in this field are also addressed. This critical review is a useful resource for all those interested in the chemical evolution of the Universe.
Download or read book Examining Abundance Anomalies in Globular Cluster Red Giant Stars written by Robert Michael Cavallo and published by . This book was released on 1998 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Star Clusters written by J.E. Hesser and published by Springer. This book was released on 1980-02-29 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the 85th Symposium on the International Astronomical Union held in Victoria, B.C., Canada, August 27-30, 1979
Download or read book Carbon and Nitrogen Abundances in the Globular Clusters M3 and M13 written by Nicholas Boris Suntzeff and published by . This book was released on 1980 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-04 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiple Populations in Globular Clusters of the Galactic Bulge written by Justin Arras Kader and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Globular clusters are a class of very old, massive, spherical, gravitationally bound star cluster which likely play an important, but as of yet unknown, role in the formation and evolution of galaxies. These clusters had been regarded as the archetypical example of simple stellar populations, with all stars having been born at the same time from the same star-forming gaseous material. One of the major predictions of such a model is that the stars in the cluster should have identical abundances, save for inhomogeneities caused by self-enrichment of red giant atmospheres via mixing of material processed in the inner layers of the evolved stars up to their surface. However, in several pivotal studies at the turn of the 21st century, star-to-star variations in atmospheric chemical abundance were discovered among unevolved stars on the main sequence of several Galactic globular clusters, prompting acceptance of a multiple populations model. It has since been demonstrated that almost all Galactic globular clusters harbor multiple populations. Several of the most popular models envision a first generation of stars forming in the protocluster with primordial abundances, followed by formation of a second generation out of intracluster material polluted with light element products of the CNO cycle (along with the NeNa- and MgAl-chain) processes. In these scenarios, the ejecta of SNe, which include Fe and other heavy elements, attains escape velocity and does not contribute to the abundances of the second generation. However, the complexity of the observed chemical trends has so far eluded comprehensive explanation, and there is still no unified model for the origin of multiple populations in globular clusters.In this dissertation, we seek to provide key constraints on competing models of the origin of multiple populations in globular clusters by studying the relative fraction of stars of different generations, and their distribution, among 14 inner Milky Way clusters which span a wide range in mass, dynamical age, and orbital characteristics. This work was made possible by use of the Blanco DECam Bulge Survey point source catalog, providing deep, wide-field, NUV-NIR broadband photometry for more than 250 million stars toward the southern Galactic bulge. Proper motions for many of the stars were available after cross-matching the photometric catalog with Gaia EDR3, which allowed for the creation of high resolution extinction maps toward the target clusters. The extinction maps allowed us to correct the photometry for the effects of differential reddening, which can be quite severe toward the Galactic bulge. By taking advantage of the de-reddened u-band, we showed that the Blanco photometry is capable of separating cluster red giant stars based on their N (Na) abundance, enabling wide-field studies of the populations in these clusters with large number statistics. With this preferentially metal-rich sample, we were able to test whether the well-known correlations between the properties of the populations and their parent clusters hold true at higher metallicity. We were also able to compare wide-field distributions of the cluster multiple populations with orbital and internal dynamical properties of the parent clusters, which are on preferentially disruptive orbits, in order to test dynamical models of the evolution of multiple populations.
Download or read book New Light on Dark Stars written by Neil Reid and published by Springer Science & Business Media. This book was released on 2006-09-01 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been very considerable progress in research into low-mass stars, brown dwarfs and extrasolar planets during the past few years, particularly since the fist edtion of this book was published in 2000. In this new edtion the authors present a comprehensive review of both the astrophysical nature of individual red dwarf and brown dwarf stars and their collective statistical properties as an important Galactic stellar population. Chapters dealing with the observational properies of low-mass dwarfs, the stellar mass function and extrasolar planets have been completely revised. Other chapters have been significantly revised and updated as appropriate, including important new material on observational techniques, stellar acivity, the Galactic halo and field star surveys. The authors detail the many discoveries of new brown dwarfs and extrasolar planets made since publication of the first edition of the book and provide a state-of-the-art review of our current knowledge of very low-mass stars, brown dwarfs and extrasolar planets, including both the latest observational results and theoretical work.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CNO Abundance Anomalies of Globular Clusters written by Todd D. Mudge and published by . This book was released on 1991 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1988 Part 1 written by U. Esser and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1266 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: "Astronomy and Astrophysics Abstracts has appeared in semi-annual volumes since 1969 and it has already become one of the fundamental publications in the fields of astronomy, astrophysics and neighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. ...The abstracts are classified under more than a hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world." Space Science Reviews#1 "Dividing the whole field plus related subjects into 108 categories, each work is numbered and most are accompanied by brief abstracts. Fairly comprehensive cross-referencing links relevant papers to more than one category, and exhaustive author and subject indices are to be found at the back, making the catalogues easy to use. The series appears to be so complete in its coverage and always less than a year out of date that I shall certainly have to make a little more space on those shelves for future volumes." The Observatory Magazine#2
Download or read book Chemical Abundances in Old Open and Metal rich Globular Clusters in the Galaxy written by Douglas Paul Geisler and published by . This book was released on 1986 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
