  We consider energy minimizing configurations of a nematic liquid crystal
around a spherical colloid particle, in the context of the Landau-de Gennes
model. The nematic is assumed to occupy the exterior of a ball of radius r_0,
satisfy homeotropic weak anchoring at the surface of the colloid, and approach
a uniform uniaxial state at infinity. We study the minimizers in two different
limiting regimes: for balls which are small compared to the characteristic
length scale r_0<<L, and for large balls, r_0>>L. The relationship between the
radius and the anchoring strength W is also relevant. For small balls we obtain
a limiting quadrupolar configuration, with a "Saturn ring" defect for
relatively strong anchoring, corresponding to an exchange of eigenvalues of the
Q-tensor. In the limit of very large balls we obtain an axisymmetric minimizer
of the Oseen-Frank energy, and a dipole configuration with exactly one point
defect is obtained.
