  We analyze the effect of the quadrupole component in the mass distribution of
a rapidly rotating neutron star on energy release in the boundary layer on the
surface of the accreting star and in the accretion disk in the cases where the
stellar radius is smaller (or larger) than the radius of the marginally stable
circular orbit. We calculate the velocities and trajectories of the particles
that fall on the stellar surface from the marginally stable orbit for a low-
luminosity accreting source. The corresponding external gravitational field of
the star is modeled by a new exact solution of the Einstein equations in
vacuum. The parameters of this solution are adjusted by reconciling the
numerical data for the radius of the marginally stable orbit and the
gravitational redshift of Cook et al. (1994) with the corresponding data in the
analytical solution. For various equations of state, we consider 1.4 solar mass
normal sequences and maximum mass normal sequences.
