U. Anzer et G. Borner, RANDOM VARIATIONS OF THE PULSE PERIOD OF X-RAY BINARIES WITH WIND ACCRETION, Astronomy and astrophysics, 299(1), 1995, pp. 62-68
In this paper we first summarise earlier results about the randomness
of pulse period variations in wind fed X-ray pulsars. Then we present
two types of models for the random spin-up and spin-down of rotating n
eutron stars which accrete mass from a stellar wind. We show that the
irregularities in accretion flows which were discovered in numerical m
odels have too low amplitudes in order to explain the observations. Th
erefore we discuss an alternative model which is based upon the existe
nce of a Kepler disc around the neutron star. We argue that such a mod
el can give an explanation of the observations.