Precessing twisted accretion disks, with an application to Hercules X-1

Journal Article · Fri Feb 15 04:00:00 EST 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157741· OSTI ID:5321370

Merritt, D; Petterson, J A

An eigenvalue equation is derived for the steady-state precession frequency of a twisted, thin accretion disk in a binary system. We describe an algorithm which solves this equation by time-evolution of the twisted disk equations. Applying the parameters of the X-ray binary Her X-1, and assuming that the 35 day cycle of that system is due to periodic obscuration by a precessing disk, we find that the observations place severe restrictions on the possible values of the viscosity in the disk. For a (twisted) ''standard'' disk model with isotropic viscosity, we find that ..cap alpha.., the dimensionless ratio of viscous-to-pressure forces in the disk, must lie in the range 1/5< or approx. =..cap alpha..< or approx. =2, with a most likely value of about 1.

• Research Organization: Princeton University Observatory
• OSTI ID: 5321370
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 236:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics &amp; Cosmology-- Stars &amp; Quasi-Stellar
Radio &amp; X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BINARY STARS
BOUNDARY CONDITIONS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DIFFERENTIAL EQUATIONS
EIGENVALUES
EQUATIONS
FLUID MECHANICS
HYDRODYNAMICS
MASS TRANSFER
MATHEMATICAL MODELS
MECHANICS
PRECESSION
STAR ACCRETION
STAR EVOLUTION
STAR MODELS
STARS
TIME DEPENDENCE
VISCOSITY