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1.
The results of 3D modeling of the formation of the accretion disks of intermediate polars are presented. A model with misaligned rotation axes of accretor and the orbit is onsidered, in which it is assumed that the white dwarf has a dipolar magnetic field with its symmetry axis inclined to the whitedwarf rotation and orbital axes. The computations show that, in the early stages of formation of the disk, the action of magnetic field is able to create the initial (seed) inclination of the disk. This inclination is then supported mainly by the dynamical pressure of the flow from the inner Lagrangian point L1. As themass of the disk increases, the inclination disappears. Under certain conditions, the disk inclination does not arise in systems with misaligned white-dwarf rotation and orbital axes. The influence of the magnetic field and asynchronous rotation of the accretor may result in the formation of spiral waves in the disk with amplitudes sufficient to be detected observationally. 相似文献
2.
D. V. Bisikalo A. V. Dodin P. V. Kaigorodov S. A. Lamzin E. V. Malogolovets A. M. Fateeva 《Astronomy Reports》2012,56(9):686-692
Speckle interferometry of the young binary system RW Aur was performed with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences using filters with central wavelengths of 550 nm and 800 nm and pass-band halfwidths of 20 nm and 100 nm, respectively. The angular separation of the binary components was 1.448?? ± 0.005?? and the position angle of the system was 255.9° ±0.3° at the observation epoch (JD 2 454 255.9). We find using published data that these values have been changing with mean rates of +0.002??/yr and +0.02°/yr, respectively, over the past 70 years. This implies that the direction of the orbital motion of the binary system is opposite to the direction of the disk rotation in RW Aur A. We propose a physical model to explain the formation of circumstellar accretion disks rotating in the reverse direction relative to young binary stars surrounded by protoplanetary disks. Our model can explain the characteristic features of the matter flow in RWAur A: the high accretion rate, small size of the disk around the massive component, and reverse direction of rotation. 相似文献
3.
The results of two-dimensional gas-dynamical numerical simulations of the structure of matter flows in the envelopes of a
number of T Tauri binary systems with elliptical orbits are considered. The main flow elements in inner regions of protoplanetary
disks of these stars are described. The influence of shocks on the size of the gap—a rarified region in the inner parts of
the protoplanetary disk—is analyzed. A method is proposed for estimating the size of this gap from the numerical simulations,
and the gap sizes for the studied stars are determined and compared with observational results. The flow dynamics in the gap
is considered, and the periodic variations of the gap size on time scales of several orbital periods are analyzed. Possible
observational manifestations of the studied flows are discussed. 相似文献
4.
A. M. Fateeva D. V. Bisikalo P. V. Kaygorodov A. Y. Sytov 《Astrophysics and Space Science》2011,335(1):125-129
We present results of 3D numerical simulations of the matter flow in the disk of a binary T Tauri star. It is shown that two
bow-shocks caused by the supersonic motion of the binary components in the gas of the disk are formed in the system having
parameters typical for T Tauri stars. These bow-shocks significantly change the flow pattern. In particular, for systems with
circular orbits they determine the size and shape of the inner gap. We also show that the redistribution of the angular momentum
due to the bow-shocks leads to occurrence of two matter flows propagating from the inner edge of the circumbinary disk to
the components. Further redistribution of this matter between the components is considered. 相似文献
5.
V. I. Shematovich P. V. Kaigorodov D. V. Bisikalo A. M. Fateeva 《Astronomy Reports》2017,61(12):1038-1043
The results of three-dimensional numerical simulations of the gaseous envelope of a contact binary star with parameters similar to those of SV Cen are presented. The outflow of matter from the vicinity of the Lagrange point L2 leads to the formation of a disk-like common envelope with a radius of order three times the component separation. The characteristics of this envelope and its structure and dynamics are discussed, as well as possible observational manifestations of such an envelope. 相似文献
6.
Turbulence in the Accretion Disks in Semi-Detached Binary Systems with Various Component-Mass Ratios
Results of three-dimensional gas-dynamical numerical simulations of the structure of matter flows in semi-detached binary systems with various component-mass ratios are considered. The main elements of the flows in the models studied are described. The characteristics of density waves inside the accretion disk for various component-mass ratios are considered. The influence of the precessional density wave on the development of instability in the accretion disks and the characteristics of developing turbulence are analyzed. Values of the Shakura–Syunyaev coefficient α for the simulated systems are calculated. 相似文献
7.
Bisikalo D. V. Sachkov M. E. Ibrahimov M. A. Savanov I. S. Nalivkin M. A. Naroenkov S. A. Fateeva A. M. Shugarov A. S. Mata Rudy Montero Pons Omar Rodriguez Rodriguez Uratsuka Marta R. 《Astronomy Reports》2022,66(1):38-41
Astronomy Reports - Beginning of operation of the first Russian–Cuban Observatory telescope, a wide-field 20-cm robotic telescope installed at the observational site optical station in... 相似文献
8.
A one-dimensional method for reconstructing the structure of prestellar and protostellar clouds is presented. The method is
based on radiative-transfer computations and a comparison of theoretical and observed intensity distributions at both millimeter
and infrared wavelengths. The radiative transfer of dust emission is modeled for specified parameters of the density distribution,
central star, and external background, and the theoretical distribution of the dust temperature inside the cloud is determined.
The intensity distributions at millimeter and IR wavelengths are computed and quantitatively compared with observational data.
The best-fit model parameters are determined using a genetic minimization algorithm, which makes it possible to reveal the
ranges of parameter degeneracy as well. The method is illustrated by modeling the structure of two infrared dark clouds IRDC-320.27+029
(P2) and IRDC-321.73+005 (P2). The derived density and temperature distributions can be used to model the chemical structure
and spectral maps in molecular lines. 相似文献
9.
D. V. Bisikalo I. S. Savanov S. A. Naroenkov M. A. Nalivkin A. S. Shugarov N. S. Bakhtigaraev P. A. Levkina M. A. Ibragimov E. Yu. Kil’pio M. E. Sachkov A. P. Kartashova A. M. Fateeva Marta R. Rodriguez Uratsuka Ramses Zaldivar Estrada Antonio Alonsa Diaz Omar Pons Rodríguez Fidel Hernandes Figuera Maritza Garcia Garcia 《Astronomy Reports》2018,62(6):367-377
The creation of a specialized network of large, wide-angle telescopes for distributed observations of near-Earth space using a Russian–Cuban Observatory is considered. An extremely important goal of routine monitoring of near-Earth and near-Sun space is warding off threats with both natural and technogenic origins. Natural threats are associated with asteroids or comets, and technogenic threats with man-made debris in near-Earth space. A modern network of ground-based optical instruments designed to ward off such threats must: (a) have a global and, if possible, uniform geographic distribution, (b) be suitable for wide-angle, high-accuracy precision survey observations, and (c) be created and operated within a single network-oriented framework. Experience at the Institute of Astronomy on the development of one-meter-class wide-angle telescopes and elements of a super-wide-angle telescope cluster is applied to determine preferences for the composition of each node of such a network. The efficiency of distributed observations in attaining maximally accurate predictions of the motions of potentially dangerous celestial bodies as they approach the Earth and in observations of space debris and man-made satellites is estimated. The first estimates of astroclimatic conditions at the proposed site of the future Russian–Cuban Observatory in the mountains of the Sierra del Rosario Biosphere Reserve are obtained. Special attention is given to the possible use of the network to carry out a wide range of astrophysical studies, including optical support for the localization of gravitational waves and other transient events. 相似文献
10.
Results of three-dimensional numerical simulations of the gas dynamics of the envelope of the young T Tauri binary star UZ Tau E are considered. The flow structure in the circumstellar envelope of the system is analyzed. It is shown that a regime with the impulsive accretion of matter from the circumstellar disk is realized in the binary system, in which there is a periodic transfer of matter to the accretion disk of the primary component through the accretion disk of the secondary.
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