  We investigate the influence of the quadrupole moment of a rotating source on
the motion of a test particle in the strong field regime. For this purpose the
Hartle-Thorne metric, that is an approximate solution of vacuum Einstein field
equations that describes the exterior of any slowly rotating, stationary and
axially symmetric body, is used. The metric is given with accuracy up to the
second order terms in the body's angular momentum, and first order terms in its
quadrupole moment. We give, with the same accuracy, analytic equations for
equatorial circular geodesics in the Hartle-Thorne spacetime and integrate them
numerically.
