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Galactic Chemical Evolution Signatures In Stellar Atmospheres And Their Possible Planetary Connection
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Book Synopsis Galactic Chemical Evolution Signatures in Stellar Atmospheres and Their Possible Planetary Connection by : Elena Nickson
Download or read book Galactic Chemical Evolution Signatures in Stellar Atmospheres and Their Possible Planetary Connection written by Elena Nickson and published by . This book was released on 2015 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Chemical Signatures of Planet Formation in Field and Open Cluster Stars by : Fan Liu
Download or read book Chemical Signatures of Planet Formation in Field and Open Cluster Stars written by Fan Liu and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, I have conducted a strictly line-by-line differential abundance analysis using high resolution, high signal-to-noise ratio spectra of field stars (e.g., stellar binaries, terrestrial planet hosts etc.) and open cluster stars (e.g., the Hyades stars) in order to identify the chemical signatures of planet formation. The three main results from this thesis are: First, we present a detailed differential abundance analysis of the HAT-P-1 stellar binary. The secondary star in this double system is known to host a transiting giant planet while no planets have yet been detected around the primary star. The derived elemental abundances of the primary and secondary stars are identical within the errors. The striking similarity in the chemical compositions of the two stellar components in HAT-P-1 indicates that the formation of giant planets does not necessarily imply differences in the chemical abundances of the host stars. Secondly, we conduct a detailed differential abundance analysis of the terrestrial planet host Kepler-10 and 14 of its stellar twins. Stellar parameters and elemental abundances of Kepler-10 and its stellar twins were obtained with very high precision. When compared to the majority of thick disc twins, Kepler-10 shows a depletion in the refractory elements relative to the volatile elements, which could be due to the formation of terrestrial planets in the Kepler-10 system. The average abundance pattern corresponds to roughly 13 Earth masses, while the two known planets in Kepler-10 system have a combined mass of 20 Earth. Although our results demonstrate that several factors (e.g., planet signature, stellar age, stellar birth location and Galactic chemical evolution) could lead to or affect abundance trends with condensation temperature, we find that the trends give further support for the planetary signature hypothesis. Thirdly, we present a high-precision differential abundance analysis of 16 solar-type stars in the Hyades open cluster. We derived stellar parameters and differential abundances for 19 elements with total uncertainties as low as 0.01 - 0.02 dex. Our main results include: (1) there is no clear chemical signature of planet formation detected among the sample stars, i.e., no correlations in elemental abundances versus condensation temperature; (2) the observed abundance dispersions are a factor of about 2 times larger than the average measurement errors for most elements; (3) there are positive correlations, of high statistical significance, between the abundances of at least 90 per cent of pairs of elements. We demonstrate that none of these findings can be explained by errors in the inferred stellar parameters. Our results reveal that the Hyades is chemically inhomogeneous at the 0.02 dex level. Possible explanations for the abundance variations include (1) inhomogeneous chemical evolution in the proto-cluster environment, (2) supernova ejection in the proto-cluster cloud, and (3) pollution of metal-poor gas before complete mixing of the proto-cluster cloud. Our results provide significant constraints on the chemical compositions of open cluster stars and for Galactic archeology, especially the concept of chemical tagging.
Book Synopsis Nucleosynthesis and Chemical Evolution of Galaxies by : Bernard E. J. Pagel
Download or read book Nucleosynthesis and Chemical Evolution of Galaxies written by Bernard E. J. Pagel and published by Cambridge University Press. This book was released on 1997-09-04 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: A lucid, wide-ranging graduate textbook on the topical subject of galactic chemical evolution - by a pioneer of the field.
Book Synopsis New Worlds, New Horizons in Astronomy and Astrophysics by : National Research Council
Download or read book New Worlds, New Horizons in Astronomy and Astrophysics written by National Research Council and published by National Academies Press. This book was released on 2011-02-04 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.
Book Synopsis Effects of Main-sequence Mass Loss on Stellar and Galactic Chemical Evolution by : Joyce Ann Guzik
Download or read book Effects of Main-sequence Mass Loss on Stellar and Galactic Chemical Evolution written by Joyce Ann Guzik and published by . This book was released on 1988 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Chemical Evolution of Galaxies by : Francesca Matteucci
Download or read book Chemical Evolution of Galaxies written by Francesca Matteucci and published by Springer Science & Business Media. This book was released on 2012-01-05 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: The term “chemical evolution of galaxies” refers to the evolution of abundances of chemical species in galaxies, which is due to nuclear processes occurring in stars and to gas flows into and out of galaxies. This book deals with the chemical evolution of galaxies of all morphological types (ellipticals, spirals and irregulars) and stresses the importance of the star formation histories in determining the properties of stellar populations in different galaxies. The topic is approached in a didactical and logical manner via galaxy evolution models which are compared with observational results obtained in the last two decades: The reader is given an introduction to the concept of chemical abundances and learns about the main stellar populations in our Galaxy as well as about the classification of galaxy types and their main observables. In the core of the book, the construction and solution of chemical evolution models are discussed in detail, followed by descriptions and interpretations of observations of the chemical evolution of the Milky Way, spheroidal galaxies, irregular galaxies and of cosmic chemical evolution. The aim of this book is to provide an introduction to students as well as to amend our present ideas in research; the book also summarizes the efforts made by authors in the past several years in order to further future research in the field.
Book Synopsis The Evolution of The Milky Way by : F. Matteucci
Download or read book The Evolution of The Milky Way written by F. Matteucci and published by Springer Science & Business Media. This book was released on 2000 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt: This review of the most up-to-date observational and theoretical information concerning the chemical evolution of the Milky Way compares the abundances derived from field stars and clusters, giving information on the abundances and dynamics of gas.
Book Synopsis Chemical Evolution of the Giant Planets by : Cyril Ponnamperuma
Download or read book Chemical Evolution of the Giant Planets written by Cyril Ponnamperuma and published by Elsevier. This book was released on 2013-10-22 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Evolution of the Giant Planets is a compilation of papers on the chemical evolution of giant planets, presented at a colloquium sponsored by the Laboratory of Chemical Evolution in October, 1974. The compendium focuses on the interpretation of data provided by the Pioneer 10 and 11 missions, which conducted explorations of the outer planets. Scientists from various disciplines tackle the various aspects of the study of the chemical environment of the giant planets and their satellites. Subjects such as the atmosphere of Jupiter and Saturn; chemical abundances in the atmospheres of the giant planets and their satellites; possibility of growth of airborne microbes in outer planetary atmospheres; and the biology on the outer planets are covered in the book. Astronomers, chemists, geologists, and biologists will find the book interesting.
Book Synopsis Resolved Chemical Evolution by : Zachary Joseph Pace
Download or read book Resolved Chemical Evolution written by Zachary Joseph Pace and published by . This book was released on 2020 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout their lives, galaxies form stars from their supply of cold gas: the largest of those stars generate heavy elements in their interiors prior to their explosive demise. As the heavy elements created in stellar evolution continually build with each generation of star formation, so do the generations of long-lived, low-mass stars. A galaxy's metal content and its total mass in stars together indicate the state of the galaxy's underlying gas reservoir: the reservoir is depleted by star formation and feedback, and is thought to be rejuvenated by inflows of low-metallicity gas from filaments of the cosmic web. However, the buildup of stellar mass is difficult to measure precisely: the observational degeneracies between stars with different ages and metallicities bring about troublesome systematics. In addition, there is little direct evidence for inflows in the local universe, though they are present in simulations and seem to be necessary to maintain gas reservoirs' star-forming vigor. In this dissertation, I develop and refine a method of measuring stellar mass-to-light ratio and other stellar population properties from medium-resolution optical spectroscopy. This method builds on a library of model star-formation histories and their associated synthetic optical spectra, and constructs a low-dimensional spectroscopic basis set capable of maximizing the predictive power of observations. This method is tested and deployed on resolved, integral-field spectroscopic observations from the SDSS-IV/MaNGA survey of nearly 10,000 nearby galaxies. Finally, I produce and release a catalog of resolved stellar mass maps and of aperture-corrected total galaxy stellar masses. I also measure resolved gas-phase metallicities in the MaNGA survey, and relate them to the mass of the galaxy-wide gas reservoir. A mutual correlation is uncovered between a steep radial metallicity profile, a large dispersion in the metallicity profile between 1.25-1.75 galaxy disk effective radii, and a large HI mass fraction relative to galaxies of the same total stellar mass. The first axis of that correlation is consistent with theoretical predictions of the signatures of radial gas flows, so I test a simple, but intuitive model of a gaseous inflow, whereby ambient metallicity is "diluted" by low-metallicity gas introduced from elsewhere. This yields estimates of the possible impact of gaseous inflows on local star-forming gas reservoirs; and indicates a means towards selecting potential inflow hosts for radio follow-up.
Book Synopsis Stellar evolution and galactic chemical evolution by : Francesca Matteucci
Download or read book Stellar evolution and galactic chemical evolution written by Francesca Matteucci and published by . This book was released on 1989 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Stellar Evolution and Galactic Chemical Evolution by : Francesca Matteucci
Download or read book Stellar Evolution and Galactic Chemical Evolution written by Francesca Matteucci and published by . This book was released on 1989 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Topics of Galactic Structure and Stellar and Chemical Evolution by : Julio César Chanamé Domínguez
Download or read book Topics of Galactic Structure and Stellar and Chemical Evolution written by Julio César Chanamé Domínguez and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In this thesis I explore current problems of Galactic astronomy by following two distinct but complementary approaches: the kinematic and photometric properties of local stellar populations, and the theory of stellar evolution. Under the first approach, I construct the largest available catalog of genuine wide binaries (a> 100 AU) and, using the relative positions of both components on a reduced proper-motion diagram, I cleanly classify them as belonging to either the disk or the halo of the Galaxy. These samples, drawn from the Revised New Luyten Two-Tenths catalog, are complete to separations of 500 and 900 arcsec, corresponding to about 0.1 and 1 parsec, respectively. At wide separations, both distributions are well described by power laws that have, within the uncertainties, identical exponents. The fact that these distributions have similar slopes and normalizations, despite the radically different Galactic environments to which they belong today, argues for similarity of the star-formation conditions of the two populations. The fact that the halo binaries obey a single power law out to about 1 parsec permits strong constraints on halo dark-matter candidates. Using Monte Carlo simulations, we exclude a halo fully composed of MAssive Compact Halo Objects (MACHOs) more massive than 43 solar masses at 95 percent confidence. I outline the prospects for using the Sloan Digital Sky Survey in the assembly of a catalog of halo wide binaries which, by improving the statistics at large separations, will enable exploration of MACHO masses in the astrophysically important regime of heavy stellar remnants. Finally, taking advantage of the identification of faint companions of Hipparcos stars, I construct a catalog of 424 intrinsically dim (i.e., low-mass) field stars with accurate (better than 3-sigma) parallaxes. Under the approach of stellar evolution, I study the long-standing problem of abundance anomalies in red giants, concentrating in non-standard mixing processes induced by stellar rotation. Unlike most previous work, I focus on the simultaneous reproduction of the CNO abundances in both Population I and Population II giants using the same physics and models. This novel approach led to a powerful new insight on one of the most difficult problems of astrophysics: the interplay between convection and rotation in stellar envelopes.
Author :National Academies of Sciences, Engineering, and Medicine Publisher :National Academies Press ISBN 13 :030947941X Total Pages :187 pages Book Rating :4.3/5 (94 download)
Book Synopsis Exoplanet Science Strategy by : National Academies of Sciences, Engineering, and Medicine
Download or read book Exoplanet Science Strategy written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-01-17 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade has delivered remarkable discoveries in the study of exoplanets. Hand-in-hand with these advances, a theoretical understanding of the myriad of processes that dictate the formation and evolution of planets has matured, spurred on by the avalanche of unexpected discoveries. Appreciation of the factors that make a planet hospitable to life has grown in sophistication, as has understanding of the context for biosignatures, the remotely detectable aspects of a planet's atmosphere or surface that reveal the presence of life. Exoplanet Science Strategy highlights strategic priorities for large, coordinated efforts that will support the scientific goals of the broad exoplanet science community. This report outlines a strategic plan that will answer lingering questions through a combination of large, ambitious community-supported efforts and support for diverse, creative, community-driven investigator research.
Book Synopsis Protostars and Planets IV by : Vincent Mannings
Download or read book Protostars and Planets IV written by Vincent Mannings and published by . This book was released on 2000 with total page 1470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Click here for the online version of this book! This title, out of print in 2008, is now available free of charge, in it's entirety, online through the University of Arizona Press! Both a textbook and a status report for every facet of research into the formation of stars and planets, Protostars and Planets IV brings together 167 authors who report on the most significant advances in the field since the publication of the previous volume in 1993. Protostars and Planets IV reflects improvements in observational techniques and the availability of new facilities such as the Infrared Space Observatory, the refurbished Hubble Space Telescope, and the 10-m Keck telescopes. Advances in computer technology and modeling methods have benefited theoretical studies of molecular clouds, star formation, and jets and disks, while recent analyses of meteorites yield important insights into conditions and processes within our Sun's early protoplanetary disk. The 49 chapters describe context and progress for observational and theoretical studies of the structure, chemistry, and dynamics of molecular clouds; the collapse of cores and the formation of protostars; the formation and properties of young binary stars; the properties of winds, jets, and molecular outflows from young stellar objects; the evolution of circumstellar envelopes and disks; grain growth in disks and the formation of planets; and the properties of the early Solar nebula. Protostars and Planets IV is also the first book to include chapters describing the discoveries of extrasolar planets, brown dwarfs, and Edgeworth-Kuiper Belt objects, and the first to include high-resolution optical and near-infrared images of protoplanetary disks. Protostars and Planets IV is an unsurpassed reference not only for established researchers but also for younger scientists whose imagination and work will lead to tomorrow's discoveries.
Book Synopsis Evolution, Atmospheres and Chemistry of Ancient Stellar Populations by : Roman Gerasimov
Download or read book Evolution, Atmospheres and Chemistry of Ancient Stellar Populations written by Roman Gerasimov and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemical diversity of our galaxy is owed to multiple generations of stars that converted the primordial mixture of hydrogen and helium into ~100 elements that make up the periodic table. The first stars to form after the Big Bang (Population III) were nearly metal-free and are believed to have been far more massive, luminous and short-lived than their later descendants. It is therefore expected that none of the Population III stars in the Milky Way survived to present day and their properties are highly debated. By contrast, the oldest metal-poor (Population II) stars that formed during or shortly after the era of Population III dominance may still be found in the galactic halo. Large numbers of those ancient stars are contained within the Milky Way globular clusters that are of particular interest to studies of stellar populations due to their coeval nature. Recent observations have confirmed that globular clusters undergo complex evolution and host multiple chemically distinct stellar populations. The physical origin of this unique feature remains largely unexplained, in part, because detailed composition measurements are only available for the most massive, spectroscopically accessible members. In order to study the early chemical evolution of the universe, I developed a method to extract the fundamental properties of chemically peculiar stellar populations from multiband photometry. My approach uniquely incorporates the calculation of new evolutionary stellar models and model atmospheres for every considered chemical composition, thereby capturing the exact relationships between individual atomic abundances and photometric colors. The computational efficiency of the fitting process is attained by identifying the components of the stellar models that are most sensitive to particular elements, and recalculating them only when the abundances of those elements are updated. In this dissertation, I describe applications of my modelling framework to the oldest stars in the universe from the elusive Population III to the ancient members of the nearby globular clusters [omega] Centauri and 47 Tucanae. I present predicted colors of metal-free stars at high redshift as they may be observed by the recently launched James Webb Space Telescope (JWST) under favorable gravitational lensing. These future observations or lack of thereof will provide strict constraints on the mass function, formation and supernova yields of the first stars. My models reproduce the entire color distribution of the main sequence stars in the globular cluster 47 Tucanae and provide a theoretical baseline for the ongoing observing campaigns with JWST that are expected to uncover the substellar cooling sequence of the cluster. The new theoretical isochrones, tailored to the chemical composition of 47 Tucanae, allow the first detailed analysis of the variation in chemical abundances with stellar mass, which is essential to determine the origin of multiple populations in globular clusters.
Book Synopsis The First Stars and Their Role in Galactic Chemical Evolution and Cosmology by : Timothy P. Ashenfelter
Download or read book The First Stars and Their Role in Galactic Chemical Evolution and Cosmology written by Timothy P. Ashenfelter and published by . This book was released on 2005 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Planets, Stars and Stellar Systems by : Gerard Gilmore
Download or read book Planets, Stars and Stellar Systems written by Gerard Gilmore and published by Springer. This book was released on 2013-02-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is volume 5 of Planets, Stars and Stellar Systems, a six-volume compendium of modern astronomical research, covering subjects of key interest to the main fields of contemporary astronomy. This volume on “Galactic Structure and Stellar Populations”, edited by Gerard F. Gilmore, presents accessible review chapters on Stellar Populations, Chemical Abundances as Population Tracers, Metal-Poor Stars and the Chemical Enrichment of the Universe, The Stellar and Sub-Stellar Initial Mass Function of Simple and Composite Populations, The Galactic Nucleus, The Galactic Bulge, Open Clusters and Their Role in the Galaxy, Star Counts and the Nature of Galactic Thick Disk, The Infrared Galaxy, Interstellar PAHs and Dust, Galactic Neutral Hydrogen, High-Velocity Clouds, Magnetic Fields in Galaxies, Astrophysics of Galactic Charged Cosmic Rays, Gamma-Ray Emission of Supernova Remnants and the Origin of Galactic Cosmic Rays, Galactic Distance Scales, Globular Cluster Dynamical Evolution, Dynamics of Disks and Warps, Mass Distribution and Rotation Curve in the Galaxy, Dark Matter in the Galactic Dwarf Spheroidal Satellites, and History of Dark Matter in Galaxies. All chapters of the handbook were written by practicing professionals. They include sufficient background material and references to the current literature to allow readers to learn enough about a specialty within astronomy, astrophysics and cosmology to get started on their own practical research projects. In the spirit of the series Stars and Stellar Systems published by Chicago University Press in the 1960s and 1970s, each chapter of Planets, Stars and Stellar Systems can stand on its own as a fundamental review of its respective sub-discipline, and each volume can be used as a textbook or recommended reference work for advanced undergraduate or postgraduate courses. Advanced students and professional astronomers in their roles as both lecturers and researchers will welcome Planets, Stars and Stellar Systems as a comprehensive and pedagogical reference work on astronomy, astrophysics and cosmology.
