  The asymptotic properties of self-similar spherically symmetric perfect fluid
solutions with equation of state p=alpha mu (-1<alpha<1) are described. We
prove that for large and small values of the similarity variable, z=r/t, all
such solutions must have an asymptotic power-law form. Some of them are
associated with an exact power-law solution, in which case they are
asymptotically Friedmann or asymptotically Kantowski-Sachs for 1>alpha >-1 or
asymptotically static for 1>alpha >0. Others are associated with an approximate
power-law solution, in which case they are asymptotically quasi-static for
1>alpha >0 or asymptotically Minkowski for 1>alpha >1/5. We also show that
there are solutions whose asymptotic behaviour is associated with finite values
of z and which depend upon powers of ln z. These correspond either to a second
family of asymptotically Minkowski solutions for 1>alpha>1/5 or to solutions
that are asymptotically Kasner for 1>alpha>-1/3. There are some other
asymptotic power-law solutions associated with negative alpha, but the physical
significance of these is unclear. The asymptotic form of the solutions is given
in all cases, together with the number of associated parameters.
