Approximate Metric for a Rotating Deformed Mass
  A new Kerr-like metric with quadrupole moment is obtained by means of
perturbing the Kerr spacetime. The form of this new metric is simple as the
Kerr metric. By comparison with the exterior Hartle-Thorne metric, it is shown
that it could be matched to an interior solution. This approximate metric may
represent the spacetime of a real astrophysical object with any Kerr rotation
parameter a and slightly deformed.
