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Paper   IPM / Astronomy / 15275
School of Astronomy
  Title:   Long-term Simulation of MHD Jet Launching in an Orbiting Star-Disk System
  Author(s): 
1.  Somayeh. Sheikhnezami
2.  Christian. Fendt
  Status:   Published
  Journal: Astrophysical Journal
  Vol.:  861
  Year:  2018
  Supported by:            ipm IPM
  Abstract:
We present fully three-dimensional magnetohydrodynamic jet-launching simulations of a jet source orbiting in a binary system. We consider a time-dependent binary gravitational potential, and thus all tidal forces are experienced in the non-inertial frame of the jet-launching primary. We investigate systems with different binary separations, different mass ratios, and different inclinations between the disk plane and the orbital plane. The simulations run over a substantial fraction of the binary orbital period. All simulations show similar local and global non-axisymmetric effects, such as local instabilities in the disk and jet or in global features, such as disk spiral arms and warps, or a global realignment of the inflow�??outflow structure. The disk accretion rate is higher than in axisymmetric simulations, most probably due to the enhanced angular momentum transport by spiral waves. The disk outflow leaves the Roche lobe of the primary and becomes disturbed by tidal effects. While a disk-orbit inclination of 10° still allows for a persistent outflow, an inclination of 30° does not, suggesting a critical angle in between. For moderate inclination, we find an indication for jet precession, such that the jet axis starts to follow a circular pattern with an opening cone of sime8°. Simulations with different mass ratios indicate a change of timescales over which the tidal forces affect the disk�??jet system. A large mass ratio (a massive secondary) leads to stronger spiral arms, higher (average) accretion, and a more pronounced jet�??counter-jet asymmetry.

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