Disk accretion by magnetic neutron stars

Journal Article · Sat Jul 15 04:00:00 EDT 1978 · Astrophys. J., Lett.; (United States)

DOI:https://doi.org/10.1086/182734· OSTI ID:6735510

Ghosh, P; Lamb, F K

We propose a model for disk accretion by a rotating magnetic neutron star which includes a detailed description of matter flow in the transition region between the disk and the magnetorspher. We show that the disk plasma cannot be completely screened from the stellar magnetic field, and that the resulting magnetic coupling between the star and the disk exerts a significant torque on the star. Assuming that the distortion of the residual stellar field lines threading the disk is limited by reconnection, we calculate the total accretion torque on the star. The calculated torque gives period changes in agreement with those observed in the pulsating X-ray sources and provides a natural explanation of why a fast rotator like Her X-1 has a spin-up rate much below the conventional estimate for slow rotators. We show that for such fast rotators, fluctuations in the mass-accretion rate can produce fluctuations in the accretion torque approx.10/sup 2/ times larger. For sufficiently fast rotators, or equivalently, for sufficiently low accretion continues and without any mass ejection from its vicinity.

• Research Organization: Department of Physics, University of Illinois at Urbana-Champaign
• OSTI ID: 6735510
• Journal Information: Astrophys. J., Lett.; (United States), Journal Name: Astrophys. J., Lett.; (United States) Vol. 223:2; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
FLUCTUATIONS
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC FIELDS
MAGNETIC STARS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
MOTION
NEUTRON STARS
PLASMA
PULSATIONS
ROTATION
STAR ACCRETION
STAR EVOLUTION
STAR MODELS
STARS
VARIATIONS