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Stratified Global M...
Stratified Global MHD Models of Accretion Disks in Semidetached Binaries
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- Pjanka, Patryk (författare)
- Stockholms universitet,KTH,Nordic Institute for Theoretical Physics NORDITA,Princeton Univ, Dept Astrophys Sci, 4 Ivy Lane, Princeton, NJ 08544 USA.,Nordiska institutet för teoretisk fysik (Nordita),Princeton University, USA
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- Stone, James M. (författare)
- Princeton Univ, Dept Astrophys Sci, 4 Ivy Lane, Princeton, NJ 08544 USA.;Inst Adv Study, 1 Einstein Dr, Princeton, NJ 08540 USA.
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(creator_code:org_t)
- 2020-11-24
- 2020
- Engelska.
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 904:2
- Relaterad länk:
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http://arxiv.org/pdf...
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visa fler...
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https://urn.kb.se/re...
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https://doi.org/10.3...
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https://urn.kb.se/re...
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visa färre...
Abstract
Ämnesord
Stäng
- We present results of the first global magnetohydrodynamic simulations of accretion disks fed by Roche-lobe overflow, including vertical stratification, in order to investigate the roles of spiral shocks, magnetorotational instability (MRI), and the accretion stream in disk structure and evolution. Our models include a simple treatment of gas thermodynamics, with orbital Mach numbers at the inner edge of the disk M-in of 5 and 10. We find mass accretion rates to vary considerably on all timescales, with only the Mach 5 model reaching a clear quasi-stationary state. For Mach 10, the model undergoes an outside-in, magnetically driven accretion event occurring on a timescale of similar to 10 orbital periods of the binary. Both models exhibit spiral shocks inclined with respect to the binary plane, with their position and inclination changing rapidly. However, the time-averaged location of these shocks in the equatorial plane is well fit by simple linear models. MRI turbulence in the disk generates toroidal magnetic field patterns (butterfly diagrams) that are in some cases irregular, perhaps due to interaction with the spiral structure. While many of our results are in good agreement with local studies, we find some features (most notably those related to spiral shocks) can only be captured in global models such as studied here. Thus, while global studies remain computationally expensive-even as idealized models-they are essential (along with more sophisticated treatment of radiation transport and disk thermodynamics) for furthering our understanding of accretion in binary systems.
Ämnesord
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- Semidetached binary stars
- Stellar accretion disks
- Magnetohydrodynamical simulations
- Cataclysmic variable stars
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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