The Contribution of Radiation Pressure to the Stability of a Standard thin Keplerian Accretion Disk around a Neutron Star with Axisymmetric Magnetic Field Dipole
No Thumbnail Available
Date
2011-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
In this thesis, we have studied the dynamic properties of an accretion disk formed from
the in
ow of plasma from a blotted out companion star. The disk extends from an inner
radius of 106m ( RA Alfeven radius) to 100RA (see gure 1.4). We have divided
the disk into three regions: an outer region dominated by gas pressure and free-free
opacity, a middle region dominated by gas pressure and electron scattering, and an inner
region dominated by radiation pressure and electron scattering. We have also derived
the radiation pressures and gas pressure in the inner region of the disk as a function of
"r" using radial dependence of the central temperature and the density. The latter was
obtained using the basic equations for thin accretion in non-relativistic case . Analyses
of the instability of the disk is made between RA and 10RA (RA < r < 10RA) based on
the instability condition ( o > 3=5). This is occurred at high temperature, at which the
opacity is dominated by electron scattering and radiation pressure is strong
Description
Keywords
Axisymmetric Magnetic Field Dipole