Download or read book Angular Momentum Transport by Nonlinear Hydrodynamic Turbulence in Protoplanetary Disks written by Andreas Drecker and published by . This book was released on 1998 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Astrophysical Disks written by S. F. Dermott and published by . This book was released on 1992 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: A companion to earlier volumes (497, 536, 596, 617 and 631) of the Annals, this entry in the nonlinear astronomy series has contributions by most of the acknowledged experts in the field. They write on many topics, all of current interest. As several hold strong opposing views, this is a lively, important and timely publication.
Download or read book Astrophysics of Planet Formation written by Philip J. Armitage and published by Cambridge University Press. This book was released on 2010 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graduate-level textbook providing a basic understanding of the astrophysical processes for readers in planetary science, and observational and theoretical astronomy.
Download or read book Magnetohydrodynamic Turbulence and Angular Momentum Transport in Accretion Disks written by Martin Elias Pessah and published by . This book was released on 2007 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is currently believed that angular momentum transport in accretion disks is mediated by magnetohydrodynamic (MHD) turbulence driven by the magnetorotational instability (MRI). More than 15 years after its discovery, an accretion disk model that incorporates the MRI as the mechanism driving the MHD turbulence is still lacking. This dissertation constitutes the first in a series of steps towards establishing the formalism and methodology needed to move beyond the standard accretion disk model and incorporating the MRI as the mechanism enabling the accretion process. I begin by presenting a local linear stability analysis of a compressible, differentially rotating flow and addressing the evolution of the MRI beyond the weak-field limit when magnetic tension forces due to strong toroidal fields are considered. Then, I derive the first formal analytical proof showing that, during the exponential growth of the instability, the mean total stress produced by correlated MHD fluctuations is positive and leads to a net outward flux of angular momentum. I also show that some characteristics of the MHD stresses that are determined during this initial phase are roughly preserved in the turbulent saturated state observed in local numerical simulations. Motivated by these results, I present the first mean-field MHD model for angular momentum transport driven by the MRI that is able to account for a number of correlations among stresses found in local numerical simulations. I point out the relevance of a new type of correlation that couples the dynamical evolution of the Reynolds and Maxwell stresses and plays a key role in developing and sustaining the MHD turbulence. Finally, I address how the turbulent transport of angular momentum depends on the magnitude of the local shear. I show that turbulent MHD stresses in accretion disks cannot be described in terms of shear-viscosity.
Download or read book Turbulent Angular Momentum Transport in Weakly ionized Accretion Disks written by Bryan Mark Johnson and published by . This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Turbulence and Self Organization written by Mikhail Ya Marov and published by Springer Science & Business Media. This book was released on 2013-01-16 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book deals with the development of continual models of turbulent natural media. Such models serve as a ground for the statement and numerical evaluation of the key problems of the structure and evolution of the numerous astrophysical and geophysical objects. The processes of ordering (self-organization) in an originally chaotic turbulent medium are addressed and treated in detail with the use of irreversible thermodynamics and stochastic dynamics approaches which underlie the respective models. Different examples of ordering set up in the natural environment and outer space are brought and thoroughly discussed, the main focus being given to the protoplanetary discs formation and evolution.
Download or read book Planetary Ring Systems written by Matthew S. Tiscareno and published by Cambridge University Press. This book was released on 2018-03-22 with total page 609 pages. Available in PDF, EPUB and Kindle. Book excerpt: Planetary rings are among the most intriguing structures of our solar system and have fascinated generations of astronomers. Collating emerging knowledge in the field, this volume reviews our current understanding of ring systems with reference to the rings of Saturn, Uranus, Neptune, and more. Written by leading experts, the history of ring research and the basics of ring–particle orbits is followed by a review of the known planetary ring systems. All aspects of ring system science are described in detail, including specific dynamical processes, types of structures, thermal properties and their origins, and investigations using computer simulations and laboratory experiments. The concluding chapters discuss the prospects of future missions to planetary rings, the ways in which ring science informs and is informed by the study of other astrophysical disks, and a perspective on the field's future. Researchers of all levels will benefit from this thorough and engaging presentation.
Download or read book Angular momentum transport and pattern formation in medium and wide gap turbulent Taylor Couette flow written by Andreas Froitzheim and published by Cuvillier Verlag. This book was released on 2019-08-26 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent Taylor-Couette flow, where the fluid is confined by two coaxial and independently rotating cylinders, is experimentally investigated within this thesis for medium and wide gaps. To reveal the influence of flow patterns on the angular momentum transport, direct torque measurements, flow visualizations and particle image velocimetry are performed in two different facilities. For the largely unexplored radius ratio regime of η = 0.357, the directly measured torque features a transition as a function of shear, which is connected to the capacity of the outer cylinder to emit small-scale plumes. When the cylinders rotate slightly in counter-direction, a maximum in torque occurs at μmax = -0.123, which is induced by the formation of large-scale Taylor vortices. The contribution of these vortices to the overall momentum transport clearly exceeds the contribution of the turbulent fluctuations for η = 0.5. Furthermore, the large-scale Taylor rolls are driven by small-scale plumes and feature azimuthally traveling waves for η = 0.714. Accordingly, the angular momentum transport in medium and wide-gap turbulent Taylor-Couette flow is determined by the interaction of turbulence and flow patterns of different scales.
Download or read book Protostellar Jets in Context written by Kanaris Tsinganos and published by Springer Science & Business Media. This book was released on 2009-09-24 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is over a quarter of a century since the discovery of out?ows from young stars. The intervening years have led to remarkable advances in our understanding of this phenomenon. Much of the progress can be attributed to advances in facilities and technologies, including not only larger telescopes but also improved instrument and detector performance. In addition protostellar out?ows have now been imaged from the ground and space at high spatial resolution, e. g. with HST, and at a wide - riety of wavelengths from X-rays to radio waves, revealing more and more about their physics. This veritable revolution in observation has been accompanied by an exponential growth in our ability to numerically simulate the launching and pro- gation of jets. Codes continue to improve: they now incorporate more physics and are increasingly ef?cient through, for example, techniques such as adaptive mesh re?nement and the use of parallel processing in cluster environments. Simulating the launching and propagation of a jet all the way from the vicinity of the star up to 4 several thousand AU (a size range of10 ) is now much closer. In more recent times, developments in observation, theory and numerical s- ulation have been joined by laboratory jet experiments reproducing, on centimetre scales, that which is seen in astrophysics to stretch for several parsecs.
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 2011-04-15 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 Meteorites Comets and Planets written by A.M. Davis and published by Elsevier. This book was released on 2005-11-21 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 1 provides a broad overview of the chemistry of the solar system. It includes chapters on the origin of the elements and solar system abundances, the solar nebula and planet formation, meteorite classification, the major types of meteorites, important processes in early solar system history, geochemistry of the terrestrial planets, the giant planets and their satellite, comets, and the formation and early differentiation of the Earth. This volume is intended to be the first reference work one would consult to learn about the chemistry of the solar system. Reprinted individual volume from the acclaimed Treatise on Geochemistry (10 Volume Set, ISBN 0-08-043751-6, published in 2003)
Download or read book Protostars and Planets VI written by Henrik Beuther and published by University of Arizona Press. This book was released on 2014-12-18 with total page 945 pages. Available in PDF, EPUB and Kindle. Book excerpt: The revolutionary discovery of thousands of confirmed and candidate planets beyond the solar system brings forth the most fundamental question: How do planets and their host stars form and evolve? Protostars and Planets VI brings together more than 250 contributing authors at the forefront of their field, conveying the latest results in this research area and establishing a new foundation for advancing our understanding of stellar and planetary formation. Continuing the tradition of the Protostars and Planets series, this latest volume uniquely integrates the cross-disciplinary aspects of this broad field. Covering an extremely wide range of scales, from the formation of large clouds in our Milky Way galaxy down to small chondrules in our solar system, Protostars and Planets VI takes an encompassing view with the goal of not only highlighting what we know but, most importantly, emphasizing the frontiers of what we do not know. As a vehicle for propelling forward new discoveries on stars, planets, and their origins, this latest volume in the Space Science Series is an indispensable resource for both current scientists and new students in astronomy, astrophysics, planetary science, and the study of meteorites.
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 Effect of Partial Mixing of Matter on the Hydrodynamic Angular Momentum Transport Processes in Massive Main sequence Stars written by Eugenij I. Staritsin and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: We consider the evolution of a rotating star with a mass of 16 Mo and an angular momentum of 3.25 x 1052 g cm2 s-1, along with the hydrodynamic transport of angular momentum and chemical elements in its interiors. When the partial mixing of matter of the turbulent radiative envelope and the convective core is taken into account, the efficiency of the angular momentum transport by meridional circulation in the stellar interiors and the duration of the hydrogen burning phase increase. Depending on the Schmidt number in the turbulent radiative stellar envelope, the ratio of the equatorial rotational velocity to the circular one increases with time in the process of stellar evolution and can become typical of early-type Be stars during an additional evolution time of the star on the main sequence. Partial mixing of matter is a necessary condition under which the hydrodynamic transport processes can increase the angular momentum of the outer stellar layer to an extent that the equatorial rotational velocity begins to increase during the second half of the evolutionary phase of the star on the main sequence, as shown by observations of the brightest stars in open star clusters with ages of 10-25 Myr. When the turbulent Schmidt number is 0.4, the equatorial rotational velocity of the star increases during the second half of the hydrogen burning phase in the convective core from 330 to 450 km s-1.
Download or read book Literature 1991 Part 2 written by Astronomisches Rechen-Institut and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 1592 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Astronomy and Astrophysics Abstracts" appearing twice a year has become oneof the fundamental publications in the fields of astronomy, astrophysics andneighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. The abstrats 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.
Download or read book Meteorites and the Early Solar System II written by Dante S. Lauretta and published by University of Arizona Press. This book was released on 2006-07 with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt: They range in size from microscopic particles to masses of many tons. The geologic diversity of asteroids and other rocky bodies of the solar system are displayed in the enormous variety of textures and mineralogies observed in meteorites. The composition, chemistry, and mineralogy of primitive meteorites collectively provide evidence for a wide variety of chemical and physical processes. This book synthesizes our current understanding of the early solar system, summarizing information about processes that occurred before its formation. It will be valuable as a textbook for graduate education in planetary science and as a reference for meteoriticists and researchers in allied fields worldwide.
