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Related papers: Dwarf Nova Outbursts with Magnetorotational Turbul…

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We study the variability of the cataclysmic variable DO Dra, on time-scales of between minutes and decades. The characteristic decay time dt/dm=0.902(3) days/mag was estimated from our 3 nights of CCD R observations. The quiescent data show…

Astrophysics · Physics 2008-06-13 I. L. Andronov , L. L. Chinarova , W. Han , Y. Kim , J. -N. Yoon

We present time dependent modeling based on the accretion disk limit cycle model for a 270 d light curve of the short period SU UMa-type dwarf nova V344 Lyr taken by Kepler. The unprecedented precision and cadence (1 minute) far surpass…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. K. Cannizzo , M. D. Still , S. B. Howell , M. A. Wood , A. P. Smale

Global three dimensional magnetohydrodynamic (MHD) simulations of turbulent accretion disks are presented which start from fully equilibrium initial conditions in which the magnetic forces are accounted for and the induction equation is…

High Energy Astrophysical Phenomena · Physics 2015-06-12 E. R. Parkin , G. V. Bicknell

We extend the one-dimensional, two-zone models of long-term protostellar disk evolution with infall of Zhu et al. to consider the potential effects of a finite viscosity in regions where the ionization is too low for the magnetorotational…

Solar and Stellar Astrophysics · Physics 2015-06-12 Jaehan Bae , Lee Hartmann , Zhaohuan Zhu , Charles Gammie

Turbulence driven by magnetorotational instability (MRI) crucially affects the evolution of solid bodies in protoplanetary disks. On the other hand, small dust particles stabilize MRI by capturing ionized gas particles needed for the…

Earth and Planetary Astrophysics · Physics 2015-05-30 Satoshi Okuzumi , Shigenobu Hirose

We propose a new method to reconstruct the structure of accretion disks in dwarf novae using multi-band light curves of early superhumps. Our model assumes that early superhumps are caused by the rotation effect of non-axisymmetrically…

Astrophysics of Galaxies · Physics 2015-06-04 M. Uemura , T. Kato , T. Ohshima , H. Maehara

The Dwarf Nova Oscillations observed in Cataclysmic Variable (CV) stars are interpreted in the context of a Low Inertia Accretor model, in which accretion on to an equatorial belt of the white dwarf primary causes the belt to vary its…

Astrophysics · Physics 2009-11-07 Brian Warner , Patrick A. Woudt

We use high-resolution time-dependent numerical simulations of accretion discs around white dwarfs to study the structure and properties of transition fronts in the context of the thermal-viscous disc instability model. The thermal…

Astrophysics · Physics 2009-10-31 Kristen Menou , Jean-Marie Hameury , Rudolf Stehle

The origin of turbulence in accretion discs is still not fully understood. While the magneto-rotational instability is considered to operate in sufficiently ionized discs, its role in the poorly ionized protoplanetary disc is questionable.…

Earth and Planetary Astrophysics · Physics 2014-12-03 Moritz H. R. Stoll , Wilhelm Kley

We argue that the quiescent value of the viscosity parameter of the accretion disc in WZ Sge may be alpha_{cold}~0.01, in agreement with estimates of alpha_{cold} for other dwarf novae. Assuming the white dwarf in WZ Sge to be magnetic, we…

Astrophysics · Physics 2008-11-26 O. M. Matthews , R. Speith , G. A. Wynn , R. G. West

The discovery of the first binary neutron star merger, GW170817, has spawned a plethora of global numerical relativity simulations. These simulations are often ideal (with dissipation determined by the grid) and/or axisymmetric (invoking ad…

High Energy Astrophysical Phenomena · Physics 2024-04-10 Loren E. Held , George Mamatsashvili , Martin E. Pessah

Layered accretion is one of the inevitable ingredients in protoplanetary disks when disk turbulence is excited by magnetorotational instabilities (MRIs). In the accretion, disk surfaces where MRIs fully operate have a high value of disk…

Earth and Planetary Astrophysics · Physics 2015-12-23 Yasuhiro Hasegawa , Taku Takeuchi

We follow the changes in the structure of the accretion disk of the dwarf nova V2051 Oph along two separate outbursts in order to investigate the causes of its recurrent outbursts. We apply eclipse mapping techniques to a set of light…

Astrophysics · Physics 2009-06-23 R. Baptista , R. F. Santos , M. Faundez-Abans , A. Bortoletto

An optical light curve of SU UMa type dwarf nova V1504 Cyg taken by Kepler was analysed in order to study fast optical variability (flickering). We calculated power density spectra and rms-flux relations for two different stages of…

Solar and Stellar Astrophysics · Physics 2015-05-21 A. Dobrotka , J. -U. Ness

Hydrodynamic, non-magnetic instabilities can provide turbulent stress in the regions of protoplanetary discs, where the MRI can not develop. The induced motions influence the grain growth, from which formation of planetesimals begins.…

Earth and Planetary Astrophysics · Physics 2017-09-06 M. G. Malygin , H. Klahr , D. Semenov , Th. Henning , C. P. Dullemond

We perform 3D vertically-stratified local shearing-box ideal MHD simulations of the magnetorotational instability (MRI) that include a net vertical magnetic flux, which is characterized by beta_0 (ratio of gas pressure to magnetic pressure…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Xue-Ning Bai , James M. Stone

We present the results of four magnetohydrodynamic simulations and one alpha-disk simulation of accretion disks in a compact binary system, neglecting vertical stratification and assuming a locally isothermal equation of state. We…

High Energy Astrophysical Phenomena · Physics 2024-11-26 Morgan Ohana , Yan-Fei Jiang , Omer Blaes , Bryance Oyang

Using local 3D MHD simulations, we investigate ways in which galactic turbulence associated with the magnetorotational instability (MRI) may influence the formation and properties of GMCs. Our disk models are vertically stratified and…

Astrophysics · Physics 2009-11-10 Woong-Tae Kim , Eve C. Ostriker , James M. Stone

Magnetorotational instability (MRI) has a potential to generate the vigorous turbulence in protoplanetary disks, although its turbulence strength and accretion stress remains debatable because of the uncertainty of MRI with low ionization…

Earth and Planetary Astrophysics · Physics 2017-11-15 Shoji Mori , Takayuki Muranushi , Satoshi Okuzumi , Shu-ichiro Inutsuka

We have developed 1D time-dependent numerical models of accretion discs, using an adaptive grid technique and an implicit numerical scheme, in which the disc size is allowed to vary with time. The code fully resolves the cooling and heating…

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