If the perturber (   ) is on a closed orbit,
Dynamical friction causes redistribution of
the orbital angular momentum:



The time needed for            or           is:




Or, in more handy units:




Application to the globular clusters and dwarf 
galaxy satellites (e.g., Magellanic Clouds): 
most of them should be gone in a Hubble time!

Dynamical friction is not very efficient in rich 
clusters of galaxies.  A typical dominant central 
("cannibal") galaxy accretes ~ 0.1 L* in a Hubble
time.