Accretion disks in cataclysmic variables. I - The eclipse-related phase shifts in DQ Herculis and UX Ursae Majoris

1980 ◽  
Vol 241 ◽  
pp. 247 ◽  
Author(s):  
J. A. Petterson
Keyword(s):  
Accretion Disks ◽  
Cataclysmic Variables ◽  
Phase Shifts ◽  
Related Phase

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 Modeling He-Rich Disks in AM CVn Binaries

2004 ◽  
Vol 194 ◽  
pp. 228-228
Author(s):  
T. Nagel ◽  
S. Dreizler ◽  
T. Rauch ◽  
K. Werner
Keyword(s):  
Accretion Disk ◽  
Time Scales ◽  
Accretion Disks ◽  
White Dwarf ◽  
Cataclysmic Variables ◽  
X Ray ◽  
Synthetic Spectra ◽  
Pure Helium ◽  
Low Mass ◽  
X Ray Binaries

We have developed a new code for the calculation of synthetic spectra and vertical structures of accretion disks in cataclysmic variables and compact X-ray binaries. Here we present results for the CV system AM CVn.AM CVn stars are a special type of cataclysmic variables, also called helium cataclysmics. They are systems of interacting binary white dwarfs, consisting of a degenerate C-O white dwarf primary and a low mass semi-degenerate secondary. The secondary loses mass, almost, pure helium, to the primary, forming an accretion disk. They have all in common a helium-rich composition, analoguous to the hydrogen-rich cataclysmic variables. They show photometric variabilities on time scales of ~ 1000s, the prototype of the class, AM CVn, e.g. exhibits a variability of ~ 18 min (Nelemans et al. 2001).

scholarly journals Model Spectra for Accretion Disks Truncated at the Inner Edge

1996 ◽  
Vol 152 ◽  
pp. 355-359
Author(s):  
Richard A. Wade ◽  
Marcos Diaz ◽  
Ivan Hubeny
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Accretion Disks ◽  
Cataclysmic Variables ◽  
Direct Impact ◽  
Innermost Part

Attempts to model the FUV spectra of accretion disks in cataclysmic variables have suggested that in some cases the innermost part of the disk is “missing”. We present computed spectra of accretion disks with various amounts of the inner disk removed arbitrarily, to illustrate whether the absence of the inner disk can be detected via the profiles of strong lines. Results are presented for lines in the UV and FUV for selected disk parameters and inclinations. UV/FUV line diagnostics can in principle establish whether the hot inner disk is present as expected from standard steady-state disk theory. The presence or absence of the inner disk has direct impact on the interpretation of the EUV spectra of cataclysmic variables, in particular the boundary layer emission.

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