Eclipse line profiles in cataclysmic variables - Evidence for absence of accretion disks

1989 ◽  
Vol 97 ◽  
pp. 1752 ◽  
Author(s):  
R. E. Williams
Keyword(s):  
Accretion Disks ◽  
Cataclysmic Variables ◽  
Line Profiles

Hydromagnetic winds from accretion disks

1986 ◽  
Vol 64 (4) ◽  
pp. 501-506 ◽  
Author(s):  
Ralph E. Pudritz ◽  
Colin A. Norman
Keyword(s):  
Accretion Disks ◽  
Energy Transport ◽  
Cataclysmic Variables ◽  
Wind Model ◽  
Ionized Gas ◽  
Molecular Outflows ◽  
Self Similar ◽  
Similar Solutions ◽  
Accretion Shock ◽  
Hoop Stresses

We present a hydromagnetic wind model for molecular and ionized gas outflows associated with protostars. If the luminosity of protostars is due to accretion, then centrifugally driven winds that arise from the envelopes of molecular disks explain the observed rates of momentum and energy transport. Ionized outflow originates from disk radii r ≤ 1015 cm inside of which Ly-continuum photons from the protostellar accretion shock are intercepted. Observed molecular outflows arise from the cool disk envelope at radii 1015 ≤ r ≤ 1017 cm. The mass-loss rates of these two component outflows are [Formula: see text] and [Formula: see text]. These winds solve the angular-momentum problem of star formation. We propose that the collimation of such outflows is due to "hoop" stresses generated by the increasingly toroidal magnetic field in the wind and suggest that the structure of the underlying disks makes self-similar solutions for these outflows likely. Finally, we apply this analysis to other accreting systems such as cataclysmic variables.

scholarly journals CVs Around the Minimum Orbital Period

2015 ◽  
Vol 2 (1) ◽  
pp. 41-45
Author(s):  
S. Zharikov ◽  
G. Tovmassian
Keyword(s):  
Accretion Disk ◽  
Accretion Disks ◽  
Orbital Period ◽  
Cataclysmic Variables ◽  
Outer Edge ◽  
Light Curves ◽  
Mass Ratio ◽  
Period Limit ◽  
Bounce Back ◽  
The Continuum

We discussed features of Cataclysmic Variables at the period minimum. In general, most of them must be WZ Sge-type objects. Main characteristics of the prototype star (WZ Sge) are discussed. A part of WZ Sge-type objects has evolved past the period limit and formed the bounce back systems. We also explore conditions and structure of accretion disks in such systems. We show that the accretion disk in a system with extreme mass ratio grows in size reaching a 2:1 resonance radius and are relatively cool. They also become largely optically thin in the continuum, contributing to the total flux less than the stellar components of the system. In contrast, the viscosity and the temperature in spiral arms formed at the outer edge of the disk are higher and their contribution in continuum plays an increasingly important role. We model such disks and generate light curves which successfully simulate the observed double-humped light curves in the quiescence.

A possible manifestation of spiral shock waves in the accretion disks of cataclysmic variables

2001 ◽  
Vol 45 (9) ◽  
pp. 676-685 ◽  
Author(s):  
D. V. Bisikalo ◽  
A. A. Boyarchuk ◽  
A. A. Kilpio ◽  
O. A. Kuznetsov
Keyword(s):  
Shock Waves ◽  
Accretion Disks ◽  
Cataclysmic Variables

Stark-broadened emission lines in the accretion disks of cataclysmic variables

1988 ◽  
Vol 327 ◽  
pp. 234 ◽  
Author(s):  
D. N. C. Lin ◽  
R. E. Williams ◽  
R. J. Stover
Keyword(s):  
Accretion Disks ◽  
Cataclysmic Variables ◽  
Emission Lines

scholarly journals Numerical Calculations for Accretion Disks in Close Binary Systems

1982 ◽  
Vol 69 ◽  
pp. 219-230 ◽  
Author(s):  
G. Hensler
Keyword(s):  
Accretion Disks ◽  
Binary Systems ◽  
Hot Spot ◽  
Cataclysmic Variables ◽  
Close Binary ◽  
Special Treatment ◽  
Theoretical Understanding ◽  
Close Binary Systems ◽  
M 10 ◽  
Good Spatial Resolution

AbstractA numerical method for 3D magnetohydrodynamical investigations of accretion disks in close binary systems is presented, which allows for good spatial resolution of structures (hot spot, accretion column). The gas is treated as individual gas cells (pseudo-particles) whose motion is calculated within a grid consisting of one spherical inner part for 3D MHD and two plane outer parts. Viscous interactions of the gas cells are taken into account by a special treatment connected with the grid geometry.We present one result of 2D hydrodynamical calculations for a binary applying the following parameters which are representative for Cataclysmic Variables: M1 = 1 Mʘ, r1 = 10-2 Rʘ, M2 = 0.5 Mʘ, p = 0.2 d, M = 10-9 Mʘ y-1.Column density and radiative flux distributions over the disk are shown and briefly discussed by comparison with the theoretical understanding of these Dwarf Novae drawn from observations.

scholarly journals New Evidence for Accretion Disks in AGNs

1989 ◽  
Vol 134 ◽  
pp. 245-250
Author(s):  
Jules P. Halpern ◽  
Kaiyou Chen
Keyword(s):  
Line Profile ◽  
Accretion Disks ◽  
Electron Scattering ◽  
Direct Evidence ◽  
Radio Galaxy ◽  
Narrow Range ◽  
Thin Disk ◽  
Line Profiles ◽  
New Evidence ◽  
Lines Of Evidence

We have refined our calculation of the line profile of a relativistic, Keplerian disk by incorporating a variety of emissivity laws, as well as broadening due to turbulence or electron scattering. The significant improvement in the fit to the double-peaked Ha line profile of the elliptical radio galaxy Arp 102B provides the most convincing direct evidence for an accretion disk in any AGN. Arp 102B appears to be a low-luminosity analog of 3C 390.3, and several lines of evidence point to the existence of small, hot ion tori illuminating an outer thin disk in both of these galaxies. The rarity of these emission-line profiles might be understood if this particular combination of ion torus/thin disk occurs only for a narrow range of ṁ(= Ṁ/ṀEdd).

scholarly journals Continuum Distributions and Line Profiles of UX UMa-Type Novalike Systems

1987 ◽  
Vol 93 ◽  
pp. 91-102
Author(s):  
K. Haug
Keyword(s):  
Boundary Layer ◽  
Accretion Disks ◽  
Wavelength Dependence ◽  
Stellar Atmosphere ◽  
Photometric Data ◽  
Balmer Line ◽  
Spectral Indices ◽  
Line Profiles ◽  
Orbital Inclination ◽  
Multi Wavelength

AbstractCombined UV, optical and, in part, IR continuum distributions of the UX UMa-systems CPD-48°1577, V3885 Sgr, RW Sex and of the recently discovered cataclysmic system PHL 227 were determined from multi-wavelength spectroscopic and photometric data to search for general characteristics of these systems. The observed variations of the UV to IR spectral indices are qualitatively very similar for all systems, whereas the absolute values show significant differences in the far and near UV ranges. The wavelength dependence of the optical and IR spectral indices as well as the variations of the Balmer line profiles lie within the range of model spectra of optically thick and stationary accretion disks with stellar atmosphere characteristics. The different behavior of the far UV spectral indices can be explained by the excess radiation from an extended and optically thick boundary layer, which depends mainly on the orbital inclination.

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