Impact of the magnetic field on the structure of accretion disks in semi-detached binaries

Жилкин, А. Г.; Bisikalo, D. V.

doi:10.1134/s1063772909050072

Cited by 22 publications

(35 citation statements)

References 25 publications

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“…These are the paths that matter can escape most easily from the gravitational field of the binary since it overcomes the lowest potential barrier, as a result requiring the lowest energy of all. The formation process and the observed features of a circumbinary envelope due to outflows from these two points have been confirmed or/and explored widely in literature (Kuiper 1941;Shu et al 1979;Soberman et al 1997;Chen et al 2006;D'Souza et al 2006;Motl et al 2007;Sytov et al 2007Sytov et al , 2009aZhilkin & Bisikalo 2009;Bisikalo 2010;Mennickent et al 2010Mennickent et al , 2012). …”

Section: Case Ii: Mass and Angular Momentum Loss Through The L2/l3 Pomentioning

confidence: 66%

Efficiency of ETV diagrams as diagnostic tools for long-term period variations

Nanouris

Kalimeris

Antonopoulou

et al. 2015

A&A

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Context. The credibility of an eclipse timing variation (ETV) diagram analysis is investigated for various manifestations of the mass transfer and gravitational radiation processes in binary systems. The monotonicity of the period variations and the morphology of the respective ETV diagrams are thoroughly explored in both the direct impact and the accretion disk mode of mass transfer, accompanied by different types of mass and angular momentum losses (through a hot-spot emission from the gainer and via the L2/L3 points). Aims. Our primary objective concerns the traceability of each physical mechanism by means of an ETV diagram analysis. Also, possible critical mass ratio values are sought for those transfer modes that involve orbital angular momentum losses strong enough to dictate the secular period changes even when highly competitive mechanisms with the opposite direction act simultaneously. Methods. TheJ −Ṗ relation that governs the orbital evolution of a binary system is set to provide the exact solution for the period and the function expected to represent the subsequent eclipse timing variations. The angular momentum transport is parameterized through appropriate empirical relations, which are inferred from semi-analytical ballistic models. Then, we numerically determine the minimum temporal range over which a particular mechanism is rendered measurable, as well as the critical mass ratio values that signify monotonicity inversion in the period modulations. Results. Mass transfer rates comparable to or greater than 10 −8 M yr −1 are measurable for typical noise levels of the ETV diagrams, regardless of whether the process is conservative. However, the presence of a transient disk around the more massive component defines a critical mass ratio (q cr ≈ 0.83) above which the period turns out to decrease when still in the conservative regime, rendering the measurability of the anticipated variations a much more complicated task. The effects of gravitational radiation proved to be rather undetectable, except for systems with physical characteristics that only refer to cataclysmic variables. Conclusions. The monotonicity of the period variations and the curvature of the respective ETV diagrams depend strongly on the accretion mode and the degree of conservatism of the transfer process. Unlike the hot-spot effects, the Lagrangian points L2 and L3 support very efficient routes of strong angular momentum loss. It is further shown that escape of mass via the L3 point -when the donor is the less massive component -safely provides critical mass ratios above which the period is expected to decrease, no matter how intense the process is.

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Section: Case Ii: Mass and Angular Momentum Loss Through The L2/l3 Pomentioning

confidence: 66%

Efficiency of ETV diagrams as diagnostic tools for long-term period variations

Nanouris

Kalimeris

Antonopoulou

et al. 2015

A&A

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“…(9) and t w ∝ 1/B * and (10) in Eq. (9). As a result, the force from the external magnetic field acting on the plasma (the last term in Eq.…”

Section: Computation Resultsmentioning

confidence: 99%

“…The numerical model takes into account the effects of diffusion of the magnetic field [in (6) and (7)] caused by magnetic reconnection and the dissipation of currents in turbulent vortices [9,14,19], magnetic buoyancy [9,14,20] and wave MHD turbulence [13,14]. The coefficient of the wave viscosity is given by…”

Section: Description Of the Modelmentioning

confidence: 99%

“…In the series of our papers [9][10][11][12][13][14][15] (see also the monograph [16]), we developed a 3D numerical model for mass transfer in semidetached binary systems taking into account the magnetic field of the accretor. The model assumes that the plasma dynamics are determined by the slow mean flow, against the background of that highspeed MHD waves propagate.…”

Section: Introductionmentioning

confidence: 99%

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A numerical model for accretion in intermediate polars with dipolar magnetic fields

2015

Self Cite

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A three-dimensional numerical model for an accretion process investigation in the magnetosphere of a white dwarf in magnetic cataclysmic variables is developed. The model assumes that the white dwarf has a dipole magnetic field with its symmetry axis inclined to the rotation axis. The model is based on the equations of modified MHD, that describe the mean flow parameters in the wave MHD turbulence. Diffusion of the magnetic field and radiative heating and cooling are taken into account. The suitability of the model is confirmed by modeling the accretion in a typical intermediate polar. The computations show that a magnetosphere forms around the accretor, with the accretion occurring via columns. The accretion columns have a curtain-like shape, and arc-shaped zones of energy release form on the surface of the white dwarf in the magnetic poles area as a result of the matter infall.

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“…However, since the problem is very complicated, the investigations have been performed either in the frame of simplified models (King 1993;Wynn & King 1995;Wynn et al 1997;King & Wynn 1999;Norton et al 2004;Ikhsanov et al 2004;Norton et al 2008), or in a limited region of the stellar magnetosphere (Koldoba et al 2002;Romanova et al 2003Romanova et al , 2004aRomanova et al , 2004b. Only over the last few years, the authors have managed to develop a comprehensive 3D numerical model to calculate the flow structure in close binaries (Zhilkin & Bisikalo 2009, 2010a, 2010b, 2010c. In our approach, we use a complete system of MHD equations that allows one to describe all 510 D. V. Bisikalo & A. G. Zhilkin the main dynamic effects concerned with the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Flow Structure in Magnetic CVs

Бисикало

Жилкин

2011

Proc. IAU

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Abstract. We present a review of the modern concept of physical processes which go on in magnetic CVs with the mass transfer between the components. Using results of 3D MHD simulations, we investigated variations of the main characteristics of accretion disks depending on the value of the magnetic induction on the surface of the accreting star. In the frame of a self-consistent description of the MHD flow structure in close binaries, we formulate conditions of the disk formation and find a criterion that separates two types of flows corresponding to intermediate polars (intermediate magnetic field) and polars (strong field).The influence of asynchronous rotation of the accretor on the flow structure in magnetic close binaries is also discussed. Simulations show that the accretion instability arising in binaries with rapid rotation of accretor ("propeller" regime) can explain the mechanism of quasi-periodic dwarf nova outbursts observed in DQ Her systems.

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Impact of the magnetic field on the structure of accretion disks in semi-detached binaries

Cited by 22 publications

References 25 publications

Efficiency of ETV diagrams as diagnostic tools for long-term period variations

Efficiency of ETV diagrams as diagnostic tools for long-term period variations

A numerical model for accretion in intermediate polars with dipolar magnetic fields

Flow Structure in Magnetic CVs

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