Numerical Simulation of the Interaction between an L1 Stream and an Accretion Disk in a Close Binary System

Fujiwara, Hajime; Makita, M.; Nagae, T.; Matsuda, Takuya

doi:10.1143/ptp.106.729

Cited by 12 publications

(31 citation statements)

References 28 publications

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“…9 we show the cross section of the L1 stream, which is bow shaped convex to the positive y direction. We obtained a similar pattern in Fujiwara et al (2001), and this was explained by the interaction of the L1 stream and the circulating circum-disc flow on the orbital plane about the primary. In the present work we realize that this explanation is not correct.…”

Section: L1 Region and L1 Streamsupporting

confidence: 58%

“…In the present study, we use the same scheme as in Makita et al (2000), Matsuda et al (2000) and Fujiwara et al (2001): the simplified flux splitting (SFS) finite-volume method proposed by Jyounouchi et al (1993) and Shima & Jyounouchi (1994). We refer to Makita et al (2000) for the numerical and the SFS schemes.…”

Section: Methodsmentioning

confidence: 99%

“…The equation of state considered here is that of an ideal gas characterized by a specific heat ratio γ, and the cases with γ = 5/3 and 7/5 are mainly studied, although the cases of γ = 1.2 and 1.01 are also considered to compare the present results with those of Fujiwara et al (2001).…”

Section: Assumptionsmentioning

confidence: 99%

“…Our main target in the present paper is to investigate the surface layer, the L1 region and the L1 stream numerically. The region around the accreting compact star has been investigated separately by our group Matsuda et al 2000;Fujiwara et al 2001). Lubow and Shu (1975) stated that "the horizontal component of the fluid velocity is parallel to isobars in the astrostrophic approximation.…”

Section: Introductionmentioning

confidence: 99%

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Numerical simulation of the surface flow of a companion star in a close binary system

Oka¹,

Nagae²,

Matsuda³

et al. 2002

A&A

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Abstract. We simulate numerically the surface flow of a gas-supplying companion star in a semi-detached binary system. Calculations are carried out for a region including only the mass-losing star, thus not the mass accreting star. The equation of state is that of an ideal gas characterized by a specific heat ratio γ, and the case with γ = 5/3 is mainly studied. A system of eddies appears on the surface of the companion star: an eddy in the low pressure region near the L1 point, one around the high pressure at the north pole, and one or two eddies around the low pressure at the opposite side of the L1 point. Gas elements starting near the pole region rotate clockwise around the north pole (here the binary system rotates counter-clockwise as seen from the north pole). Because of viscosity, the gas drifts to the equatorial region, switches to the counter-clockwise eddy near the L1 point and flows through the L1 point to finally form the L1 stream. The flow field in the L1 region and the structure of the L1 stream are also considered.

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Section: L1 Region and L1 Streamsupporting

confidence: 58%

Section: Methodsmentioning

confidence: 99%

Section: Assumptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical simulation of the surface flow of a companion star in a close binary system

Oka¹,

Nagae²,

Matsuda³

et al. 2002

A&A

Self Cite

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“…The method of computational fluid dynamics is described in [30] and details are explained in [31,32]. We use the simplified flux vector splitting (SFS) finite volume scheme to discretize the Euler equation (the description of the SFS scheme is given in the appendix of [31]).…”

Section: The Modelmentioning

confidence: 99%

Three-dimensional gas-dynamical modeling of changes in the flow structure during the transition from the quiescent to the active state in symbiotic stars

et al. 2005

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The results of 3D modelling of the flow structure in the classical symbiotic system Z Andromedae are presented. Outbursts in systems of this type occur when the accretion rate exceeds the upper limit of the steady burning range. Therefore, in order to realize the transition from a quiescent to an active state it is necessary to find a mechanism able to sufficiently increase the accretion rate on a time scale typical to the duration of outburst development.Our calculations have confirmed the transition mechanism from quiescence to outburst in classic symbiotic systems suggested earlier on the basis of 2D calculations (Bisikalo et al, 2002). The analysis of our results have shown that for wind velocity of 20 km/s an accretion disc forms in the system. The accretion rate for the solution with 1 2 the disc is ∼ 22.5 − 25% of the mass loss rate of the donor, that is, ∼ 4.5 − 5 · 10 −8 M ⊙ /yr for Z And. This value is in agreement with the steady burning range for white dwarf masses typically accepted for this system. When the wind velocity increases from 20 to 30 km/s the accretion disc is destroyed and the matter of the disc falls onto the accretor's surface. This process is followed by an approximately twofold accretion rate jump. The resulting accretion rate growth is sufficient for passing the upper limit of the steady burning range, thereby bringing the system into an active state. The time during which the accretion rate is above the steady burning value is in a very good agreement with observations.The analysis of the results presented here allows us to conclude that small variations in the donor's wind velocity can lead to the transition from the disc accretion to the wind accretion and, as a consequence, to the transition from quiescent to active state in classic symbiotic stars.

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Gas flow in Close Binary Star Systems

Matsuda

Oka

Hachisu

et al.

Notes on Numerical Fluid Mechanics and Multidisciplinary Design (NNFM)

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We first present a summary of our numerical work on accretion discs in close binary systems. Our recent studies on numerical simulations of the surface flow on the mass-losing star in a close binary star is then reviewed. Accretion discsAn accretion disc around a compact star in a close binary star system is an ubiquitous and essential object. Accretion discs play, for example, important roles in cataclysmic variables, nova and X-ray sources. The standard theory to explain the physics in accretion discs is the α-disc model proposed by Shakura and Sunyaev (1973). In this theory, the accretion disc is in some kind of turbulent state, in which turbulent viscosity is parameterized by a phenomenological parameter α.However, the α-disc model is rather crude approximation to an accretion disc in a close binary system: tidal effects due to the companion star are, for example, not taken into account. To better take these effects into account, one has to rely on numerical simulations.

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Numerical Simulation of the Interaction between an L1 Stream and an Accretion Disk in a Close Binary System

Cited by 12 publications

References 28 publications

Numerical simulation of the surface flow of a companion star in a close binary system

Numerical simulation of the surface flow of a companion star in a close binary system

Three-dimensional gas-dynamical modeling of changes in the flow structure during the transition from the quiescent to the active state in symbiotic stars

Gas flow in Close Binary Star Systems

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