Self-similar hot accretion on to a spinning neutron star: matching the outer boundary conditions

  title={Self-similar hot accretion on to a spinning neutron star: matching the outer boundary conditions},
  author={Ramesh Narayan and Mikhail V. Medvedev},
  journal={Monthly Notices of the Royal Astronomical Society},
Medvedev & Narayan have described a hot accretion flow on to a spinning neutron star in which the gas viscously brakes the spin of the star. Their self-similar solution has the surprising property that the density, temperature and angular velocity of the gas at any radius are completely independent of the outer boundary conditions. Hence, the solution cannot be matched to a general external medium. We resolve this paradoxical situation by showing that there is a second self-similar solution… Expand

Figures from this paper

Boundary Layer Self-Similar Solution for the Hot Radiative Accretion onto a Rapidly Spinning Neutron Star
We consider hot accretion onto a rapidly spinning neutron star (or any other compact object with a surface). A radiative hot settling flow was discovered at low accretion rates in the early work byExpand
Mass Accretion Rate of Rotating Viscous Accretion Flow
The mass accretion rate of transonic spherical accretion flow onto compact objects such as black holes is known as the Bondi accretion rate, which is determined only by the density and theExpand
4U 2206+54 is a high-mass X-ray binary which has been suspected to contain a neutron star accreting from the wind of its companion, BD +53{sup 0} 2790. Reig et al. have recently detected 5560 sExpand
Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields
This paper summarizes the results obtained by the team “Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields” supported by theExpand
Theory and Applications of Non-Relativistic and Relativistic Turbulent Reconnection
Realistic astrophysical environments are turbulent due to the extremely high Reynolds numbers. Therefore, the theories of reconnection intended for describing astrophysical reconnection should notExpand
An X-ray-UV correlation in Cen X-4 during quiescence
Quiescent emission from the neutron star low-mass X-ray binary Cen X-4 is seen to be variable on time-scales from hundreds of seconds to years, suggesting that at least in this object, low-levelExpand


Self-similar Hot Accretion Flow onto a Neutron Star
We consider hot, two-temperature, viscous accretion onto a rotating, unmagnetized neutron star. We assume Coulomb coupling between the protons and electrons, as well as free-free cooling from theExpand
Hot Atmospheres around Accreting Neutron Stars: A Possible Source for Hard X-Ray Emission
The structure of static atmospheres around unmagnetized neutron stars undergoing steady spherical accretion is discussed. We focus on the hot configurations presented earlier by Turolla et al. andExpand
We study the structure and properties of hot MHD accretion onto a Kerr black hole (BH). In such a system, the hole is magnetically coupled to the inflowing gas and exerts a torque onto the accretionExpand
On the accretion luminosity of isolated neutron stars
The accretion process onto a magnetized isolated neutron star, which captures material from the interstellar medium, is discussed. The evolutionary track of such a star can be presented as a sequenceExpand
Spherical Accretion onto Neutron Stars Revisited: Are Hot Solutions Possible ?
Stationary, spherical accretion onto an unmagnetized neutron star is here reconsidered on the wake of the seminal paper by Zel'dovich \& Shakura (1969). It is found that new ``hot'' solutions mayExpand
Hot Accretion onto White Dwarfs in Quiescent Dwarf Novae
We present dynamically consistent solutions for hot accretion onto unmagnetized, rotating white dwarfs (WDs) in five quiescent dwarf novae. The measured WD rotation rates (and other systemExpand
We consider height-integrated equations of an advection-dominated accretion flow (ADAF), assuming that there is no mass outflow. We include convection through a mixing-length formalism. We seekExpand
The role of viscosity and cooling mechanisms in the stability of accretion disks.
A dispersion relation for linearized perturbation of a geometrically thin accretion disk is derived for an arbitrary viscosity law and cooling mechanism. Using this equation, we formulate theExpand
Hard X-rays from accretion disk boundary layers
ACCRETION disks1,2 are found in many astrophysical objects, ranging from newly formed stars and mass-transferring binary systems to quasars and other active galactic nuclei. An important feature ofExpand
Convection-dominated Accretion Flows
Nonradiating advection-dominated accretion flows are convectively unstable in the radial direction. We calculate the two-dimensional (r-θ) structure of such flows assuming that (1) convectionExpand