Numerical Studies of Gravitational Accretion from X-Ray Heated Stellar Winds PDF Download
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Author: James Anthony Lupo
Publisher:
ISBN:
Category : Accretion (Astrophysics)
Languages : en
Pages : 153
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Book Description
We present three numerical models of accretion from radiation driven stellar winds onto compact objects in massive X-ray binary systems. The wind is given a velocity profile consistent with a radiatively driven wind, and a 'negative mass' gravitational potential is derived from this profile to represent the wind driving force in the hydrodynamic equations. An X-ray heating model is used which determines the X-ray heating time from the Compton heating time and the known steady state energies for optically thin gas illuminated by X-rays. This allows X-ray heating to be included in the hydrodynamic equations. The X-ray luminosity is held proportional to the accretion rate, assuming that the gravitational potential energy released is equivalent to 10% of the infalling rest-mass energy. A two-dimensional Eulerian computer code is used to solve the equations of motion. Model estimates of the ionization structure, accretion rates and flow characteristics, and the effects of thermal instabilities are discussed. The impact of the X-ray radiation on the wind driving force is demonstrated. Results indicate a possible mechanism for slow X-ray flares, such as observed in 4U1700-37.
Author: James Anthony Lupo
Publisher:
ISBN:
Category : Accretion (Astrophysics)
Languages : en
Pages : 153
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Book Description
We present three numerical models of accretion from radiation driven stellar winds onto compact objects in massive X-ray binary systems. The wind is given a velocity profile consistent with a radiatively driven wind, and a 'negative mass' gravitational potential is derived from this profile to represent the wind driving force in the hydrodynamic equations. An X-ray heating model is used which determines the X-ray heating time from the Compton heating time and the known steady state energies for optically thin gas illuminated by X-rays. This allows X-ray heating to be included in the hydrodynamic equations. The X-ray luminosity is held proportional to the accretion rate, assuming that the gravitational potential energy released is equivalent to 10% of the infalling rest-mass energy. A two-dimensional Eulerian computer code is used to solve the equations of motion. Model estimates of the ionization structure, accretion rates and flow characteristics, and the effects of thermal instabilities are discussed. The impact of the X-ray radiation on the wind driving force is demonstrated. Results indicate a possible mechanism for slow X-ray flares, such as observed in 4U1700-37.
Author: Marvin Leonard Alme
Publisher:
ISBN:
Category :
Languages : en
Pages : 408
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Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 596
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Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Author:
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ISBN:
Category : Power resources
Languages : en
Pages : 844
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Author:
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ISBN:
Category : Nuclear energy
Languages : en
Pages : 988
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Author: Chengmin Zhang
Publisher: Cambridge University Press
ISBN: 9781107033795
Category : Science
Languages : en
Pages : 0
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Book Description
This decade has seen a large number of high-energy space missions, which, alongside ground-based optical and radio telescopes, have enabled the detailed study of accreting compact objects. IAU S290 addresses the state-of-the-art research on accretion in astrophysical objects and systems ranging in scale from active galactic nuclei down to stellar black holes, neutron stars and white dwarfs, by bringing together scientists from each of these fields. It focuses on understanding the common physics of slow and relativistic outflows in these objects and features reviews on modelling, observations and instrumentation. Specific topics covered in this volume include: the physics of accreting systems, the magnetic environment around compact objects, large scale properties of accretion, the accretion-ejection connection, jets and outflows, and instrumentation. The fundamentals of accretion and its applications are reviewed in several of the papers, making this a useful reference guide for researchers and graduate students in astrophysics.
Author: Nikolay Shakura
Publisher: Springer
ISBN: 3319930095
Category : Science
Languages : en
Pages : 437
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Book Description
This book highlights selected topics of standard and modern theory of accretion onto black holes and magnetized neutron stars. The structure of stationary standard discs and non-stationary viscous processes in accretion discs are discussed to the highest degree of accuracy analytic theory can provide, including relativistic effects in flat and warped discs around black holes. A special chapter is dedicated to a new theory of subsonic settling accretion onto a rotating magnetized neutron star. The book also describes supercritical accretion in quasars and its manifestation in lensing events. Several chapters cover the underlying physics of viscosity in astrophysical discs with some important aspects of turbulent viscosity generation. The book is aimed at specialists as well as graduate students interested in the field of theoretical astrophysics.
Author:
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 1384
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Author: Astronomisches Rechen-InstitutARI
Publisher: Springer Science & Business Media
ISBN: 3642517587
Category : Science
Languages : en
Pages : 1746
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Book Description
Astronomy and Astrophysics Abstracts is devoted to the recording, summarizing and indexing of astronomical publications throughout the world. Two volumes are scheduled to appear per year. Volume 67 records 10,903 papers covering besides the classical fields of astronomy and astrophysics such matters as space flights related to astronomy, lunar and planetary probes and satellites, meteorites and interplanetary matter, X rays and cosmic rays, quasars and pulsars. The abstracts are classified under more than one hundred subject categories thus permitting quick surveying of the bulk of material published on the same topic within six months. For instance, this volume records 119 papers on minor planets, 155 papers on supernovae, and 554 papers on cosmology.
Author:
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ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 806
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