Download or read book Accretion Disks and the Formation of Stellar Systems written by Kaitlin Michelle Kratter and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we examine the role of accretion disks in the formation of stellar systems, focusing on young massive disks which regulate the flow of material from the parent molecular core down to the star. We study the evolution of disks with high infall rates that develop strong gravitational instabilities. We begin in chapter 1 with a review of the observations and theory which underpin models for the earliest phases of star formation and provide a brief review of basic accretion disk physics, and the numerical methods which we employ. In chapter 2 we outline the current models of binary and multiple star formation, and review their successes and shortcomings from a theoretical and observational perspective. In chapter 3 we begin with a relatively simple analytic model for disks around young, very massive stars, showing that instability in these disks may be responsible for the higher multiplicity fraction of massive stars, and perhaps the upper mass to which they grow. We extend these models in chapter 4 to explore the properties of disks and the formation of binary companions across a broad range of stellar masses. In particular, we model the role of global and local mechanisms for angular momentum transport in regulating the relative masses of disks and stars. We follow the evolution of these disks throughout the main accretion phase of the system, and predict the trajectory of disks through parameter space. We follow up on the predictions made in our analytic models with a series of high resolution, global numerical experiments in chapter 5. Here we propose and test a new parameterization for describing rapidly accreting, gravitationally unstable disks. We find that disk properties and system multiplicity can be mapped out well in this parameter space. Finally, in chapter 6, we address whether our studies of unstable disks are relevant to recently detected massive planets on wide orbits around their central stars.
Download or read book Accretion Processes in Star Formation written by Lee Hartmann and published by Cambridge University Press. This book was released on 2000-11-15 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive account of the dynamical processes in the formation of stars and disks from which planets ultimately form.
Download or read book Theory of Accretion Disks written by F. Meyer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the advent of space observatories and modern developments in ground based astronomy and concurrent progress in the theoretical understanding of these observations it has become clear that accretion of material on to compact objects is an ubiquitous mechanism powering very diverse astrophysical sources ranging in size and luminosity by many orders of magnitude. A problem common to these systems is that the material accreted must in general get rid of its angular momentum and this leads to the formation of an Accretion Disk which allows angular momentum re-distribution and converts potential energy into radiation with an efficiency which can be higher than the nuclear burning yield. These systems range in size from quasars and active galactic nuclei to accretion disks around forming stars and the early solar system and to compact binaries such as cataclysmic variables and low-mass X-ray binaries. Other objects that should be mentioned in this context are 88433, the black hole binary candidates, and possibly gamma-ray burst sources. Observations of these systems have provided important constraints for theoretical accretion disk models on widely differing scales, lumi nosities, mass-transfer rates and physical environments.
Download or read book Physics of Accretion Disks written by S Kato and published by CRC Press. This book was released on 1996 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advection-dominated disks are replacing the standard model, and this book provides the first extensive examination of their various aspects. Topics discussed include the global disk structure, thermal stability, two-temperature regimes, electron-positron pair production, disk spectra, the relation to the outburst behaviour of X-ray transients and hard-soft spectral transitions, the effects of radiation drag force, jet formation and possible nucleosynthesis in the advection-dominated disks. The papers also address some more fundamental issues concerning the basic physics of accretion disks, including the origin of disk viscosity, the observational appearance of the tidal instability. In cataclysmic variables, and the role of self-gravity of accretion disks in relation to stellar systems and to star/planet formation. This book will be required reading for any astronomer, cosmologist or astrophysicist seeking an up-to-date overview of this topic.
Download or read book Origin of the Solar System written by Dr. Milton M. Beck and published by AuthorHouse. This book was released on 2023-07-24 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the reasons why the author does not believe the accretion disk origin theory for our solar system. That theory might fit other system, but not ours. The author first shows reasons why the currently accepted theory doesn’t fit. He goes from one facet of the accretion disk theory to another discrediting each in turn. The author then describes his own theory. The author has made a good effort to define a sequence of events that resulted in our solar system. How well his theory is accepted remains to be seen, but he asks for a fair chance for its evaluation. He presents an interesting idea.
Download or read book Accretion Disks in Compact Stellar Systems written by J. Craig Wheeler and published by Advanced Astrophysics and Cosm. This book was released on 1993 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accretion disks in compact stellar systems containing white dwarfs, neutron stars or black holes are the principal laboratory for understanding the role of accretion disks in a wide variety of environments from proto-stars to quasars. Recent work on disk instabilities and dynamics has given a new theoretical framework with which to study accretion disks. Modeling of time-dependent phenomena provides new insight into the causes and interpretation of photometric and spectroscopic variability and new constraints on the fundamental physical problem -- the origin of viscosity in accretion disks. This book contains expert reviews on the nature of limit cycle thermal instabilities and a variety of closely related topics from the theory of angular momentum transport to eclipse mapping of the disk structure. The result is a comprehensive contemporary survey of the structure and evolution of accretion disks in compact binary systems.
Download or read book On the Role of Disks in the Formation of Stellar Systems written by and published by . This book was released on 2009 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: We study rapidly accreting, gravitationally unstable disks with a series of idealized global, numerical experiments using the code ORION. Our numerical parameter study focuses on protostellar disks, showing that one can predict disk behavior and the multiplicity of the accreting star system as a function of two dimensionless parameters which compare the infall rate to the disk sound speed and orbital period. Although gravitational instabilities become strong, we find that fragmentation into binary or multiple systems occurs only when material falls in several times more rapidly than the canonical isothermal limit. The disk-to-star accretion rate is proportional to the infall rate and governed by gravitational torques generated by low-m spiral modes. Furthermore, we also confirm the existence of a maximum stable disk mass: disks that exceed 5̃0% of the total system mass are subject to fragmentation and the subsequent formation of binary companions.
Download or read book Formation Evolution and Dynamics of Young Solar Systems written by Martin Pessah and published by Springer. This book was released on 2017-12-04 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book's interdisciplinary scope aims at bridging various communities: 1) cosmochemists, who study meteoritic samples from our own solar system, 2) (sub-) millimetre astronomers, who measure the distribution of dust and gas of star-forming regions and planet-forming discs, 3) disc modellers, who describe the complex photo-chemical structure of parametric discs to fit these to observation, 4) computational astrophysicists, who attempt to decipher the dynamical structure of magnetised gaseous discs, and the effects the resulting internal structure has on the aerodynamic re-distribution of embedded solids, 5) theoreticians in planet formation theory, who aim to piece it all together eventually arriving at a coherent holistic picture of the architectures of planetary systems discovered by 6) the exoplanet observers, who provide us with unprecedented samples of exoplanet worlds. Combining these diverse fields the book sheds light onto the riddles that research on planet formation is currently confronted with, and paves the way for a comprehensive understanding of the formation, evolution, and dynamics of young solar systems. The chapters ‘Chondrules – Ubiquitous Chondritic Solids Tracking the Evolution of the Solar Protoplanetary Disk’, ‘Dust Coagulation with Porosity Evolution’ and ‘The Emerging Paradigm of Pebble Accretion’ are published open access under a CC BY 4.0 license via link.springer.com.
Download or read book Accretion Disks In Compact Stellar Systems written by J Craig Wheeler and published by World Scientific. This book was released on 1993-12-22 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accretion disks in compact stellar systems containing white dwarfs, neutron stars or black holes are the principal laboratory for understanding the role of accretion disks in a wide variety of environments from proto-stars to quasars. Recent work on disk instabilities and dynamics has given a new theoretical framework with which to study accretion disks. Modeling of time-dependent phenomena provides new insight into the causes and interpretation of photometric and spectroscopic variability and new constraints on the fundamental physical problem — the origin of viscosity in accretion disks. This book contains expert reviews on the nature of limit cycle thermal instabilities and a variety of closely related topics from the theory of angular momentum transport to eclipse mapping of the disk structure. The result is a comprehensive contemporary survey of the structure and evolution of accretion disks in compact binary systems.
Download or read book Physics of Accretion Disks written by and published by . This book was released on 1996 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handboek over de omgang met paarden.
Download or read book From Protoplanetary Disks to Planet Formation written by Philip J. Armitage and published by Springer. This book was released on 2019-02-02 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Is the Sun and its planetary system special? How did the Solar system form? Are there similar systems in the Galaxy? How common are habitable planets? What processes take place in the early life of stars and in their surrounding circumstellar disks that could impact whether life emerges or not? This book is based on the lectures by Philip Armitage and Wilhelm Kley presented at 45th Saas-Fee Advanced Course „From Protoplanetary Disks to Planet Formation“ of the Swiss Society for Astrophysics and Astronomy. The first part deals with the physical processes occurring in proto-planetary disks starting with the observational context, structure and evolution of the proto-planetary disk, turbulence and accretion, particle evolution and structure formation. The second part covers planet formation and disk-planet interactions. This includes in detail dust and planetesimal formation, growth to protoplanets, terrestrial planet formation, giant planet formation, migration of planets, multi-planet systems and circumbinary planets. As Saas-Fee advanced course this book offers PhD students an in-depth treatment of the topic enabling them to enter on a research project in the field.
Download or read book Planet Formation written by Wolfgang Brandner and published by Cambridge University Press. This book was released on 2011-02-17 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: When this book was published in 2006, it had been just over ten years since the first planet outside our solar system was detected. Since then, much work has focused on understanding how extrasolar planets may form, and discovering the frequency of potentially habitable Earth-like planets. This volume addresses fundamental questions concerning the formation of planetary systems in general, and of our solar system in particular. Drawing from advances in observational, experimental and theoretical research, it summarises our understanding of the planet formation processes, and addresses major open questions and research issues. Chapters are written by leading experts in the field of planet formation and extrasolar planet studies. The book is based on a meeting held at Ringberg Castle in Bavaria, where experts gathered together to present and exchange their ideas and findings. It is a comprehensive resource for graduate students and researchers, and is written to be accessible to newcomers to the field.
Download or read book Astrophysical Disks written by Aleksey M. Fridman and published by Springer Science & Business Media. This book was released on 2006-07-25 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with collective and stochastic processes in astrophysical disks involving theory, observations, and the results of modelling. It examines the spiral-vortex structure in galactic and accretion disks, and stochastic and ordered structures in developed turbulence. The book advances the study in this important branch of astrophysics and will benefit professional researchers, lecturers, and graduate students.
Download or read book The Origin of Stars and Planetary Systems written by Charles J. Lada and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt: A few years after the publication of The Physics of Star Formation and Early Stellar Evolution, we received a request from the publisher for an up dated second edition of this popular reference book. As originally intended, the volume had proved to be a useful "text" book for graduate astronomy courses and seminars which dealt with topics related to stellar origins. The book was based on a series of lectures delivered by a distinguished group of leading researchers at a NATO Advanced Study Institute (ASI) held in May 1990 on the island of Crete, Greece. The primary goal of the ASI was in fact to produce a book which "would simultaneously provide a broad and systematic overview of, as well as a rigorous introduction to, the fun damental physics and astronomy at the heart of modern research in star formation and early stellar evolution. " However, by 1995 concern had arisen among those who used the text as a reference for graduate seminars and courses that the book would need to be updated to stay abreast of the discoveries and progress in this rapidly evolving field. After some discussion we concluded that a new edition of the book was warranted and that the goal of producing a new edition would be best accomplished by organizing a second ASI in Crete to review the progress in star formation research.
Download or read book Physical Processes in Circumstellar Disks Around Young Stars written by Paulo J. V. Garcia and published by University of Chicago Press. This book was released on 2011-05-15 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Circumstellar disks are vast expanses of dust that form around new stars in the earliest stages of their birth. Predicted by astronomers as early as the eighteenth century, they weren’t observed until the late twentieth century, when interstellar imaging technology enabled us to see nascent stars hundreds of light years away. Since then, circumstellar disks have become an area of intense study among astrophysicists, largely because they are thought to be the forerunners of planetary systems like our own—the possible birthplaces of planets. This volume brings together a team of leading experts to distill the most up-to-date knowledge of circumstellar disks into a clear introductory volume. Understanding circumstellar disks requires a broad range of scientific knowledge, including chemical processes, the properties of dust and gases, hydrodynamics and magnetohydrodynamics, radiation transfer, and stellar evolution—all of which are covered in this comprehensive work, which will be indispensable for graduate students, seasoned researchers, or even advanced undergrads setting out on the study of planetary evolution.
Download or read book The Physics of Star Formation and Early Stellar Evolution written by Charles J. Lada and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 779 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin of stars is one of the principle mysteries of nature. During the last two decades advances in technology have enabled more progress to be made in the quest to understand stellar origins than at any other time in history. The study of star formation has developed into one of the most important branches of mod ern astrophysical research. A large body of observational data and a considerable literat ure now exist concerning this topic and a 1arge community of international astronomers and physicists devote their efforts attempting to decipher the secrets of stellar birth. Yet, the young astronomerjphysicist or more advanced researcher desiring to obtain a basic background in this area of research must sift through a very diverse and sometimes bewildering literature. A literature which includes research in many discip1ines and sub discip1ines of classical astrophysics from stel lar structure to the interstellar medium and encompasses the entire range of the electromagnetic spectrum from radio to gamma rays. Often, the reward of a suc cessfu1 foray through the current literature is the realization that the results can be obsolete and outdated as soon as the ink is dry in the journal or the conference proceeding in which they are published.
Download or read book Planetary Systems Formation Evolution and Detection written by Bernard F. Burke and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: `Are there other planetary systems like ours? Other planets like ours? Is there life elsewhere in the Universe?' So asks Dr. Lew Allen Jr. in the Foreword. In December of 1992, theorists, observers, and instrument builders gathered at the California Institute of Technology to discuss the search for answers to these questions. The International Conference, entitled `Planetary Systems: Formation, Evolution, and Detection' and supported through NASA's newly formed TOPS (Toward Other Planetary Systems) program, was the first of a series of conferences uniting researchers across disciplines and political boundaries to share thoughts and information on planetary systems. The conference was sponsored by NASA, hosted by JPL at Caltech, and endorsed by the 1992 International Space Year Association. These proceedings include discussions of topics ranging from stellar, disk, and planetary formation to new ways of searching for other stellar systems containing planets. The authors represent a wide range of nationalities, disciplines, and points of view. The second international conference took place in December of 1993.
