Establish the physical sustainability of the disc-generated negative torque

Establish whether the negative torque predicted by the analytic star–disc boundary prescription can be sustained when the outer disc boundary condition, donor-star truncation, mass-transfer stream interaction, radiative pressure, disc warping, and time-dependent behaviour are treated in multidimensional hydrodynamic models.

Background

The proposed mechanism allows a rapidly rotating accretor to continue gaining mass while the disc removes angular momentum through a negative torque. However, the analytic model omits several physical effects that may alter the torque, including the outer boundary condition, truncation by the donor, interaction with the incoming stream, radiation forces, warping, and time dependence. The paper identifies multidimensional hydrodynamic calculations as necessary to resolve whether the torque survives under realistic conditions.