A model for the recurrent flares in EXO 2030 + 375

It is shown that nonsteady hydrodynamical flows associated with mass and angular momentum capture by a neutron star during a mass ejection phase from a Be star can produce flares with remarkable resemblance to those observed during an outburst from the X-ray transient pulsar EXO 2030 + 375. To reproduce the recurrent time scale of the flares, the velocity of the outflowing matter is estimated to be about 550 km/s. Since the theoretical model requires that a transient disk circulating in one direction is followed by a transient disk circulating in the opposite direction, the time derivative of the pulse period is expected to change sign after each flare event.