Angular momentum transport through magnetic accretion curtains inside disrupted discs

Abstract

The structure of accretion curtain flows arising from magnetically disrupted discs is considered. It is shown that a sub-Alfvenic, magnetically channelled flow is consistent with matching the magnetic field across the curtain base. It is shown that some angular momentum is necessarily fed back into the disc, and this reduces the accretion torque acting on the star. The sonic point coordinates are found and a critical rotation rate results below which the sonic point merges with the curtain flow base so, for such stellar rotation rates, little or no thermal assistance is required for material to make the transition to a supersonic flow.

12 pages, 1 figure, accepted for MNRAS

References in corpus (3)

• Three-dimensional Simulations of Disk Accretion to an Inclined Dipole: I. Magnetospheric Flow at Different Theta
• The spin of accreting stars: dependence on magnetic coupling to the disc
• On the Rotational Dynamics of Magnetically Threaded Disks around Neutron Stars

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• Constraints on the magnetic field structure in accreting compact objects from aperiodic variability