  Infrared studies have revealed debris likely related to planet formation in
orbit around ~30% of youthful, intermediate mass, main sequence stars. We
present evidence, based on atmospheric pollution by various elements heavier
than helium, that a comparable fraction of the white dwarf descendants of such
main sequence stars are orbited by planetary systems. These systems have
survived, at least in part, through all stages of stellar evolution that
precede the white dwarf. During the time interval (~200 million years) that a
typical polluted white dwarf in our sample has been cooling it has accreted
from its planetary system the mass of one of the largest asteroids in our solar
system (e.g., Vesta or Ceres). Usually, this accreted mass will be only a
fraction of the total mass of rocky material that orbits these white dwarfs;
for plausible planetary system configurations we estimate that this total mass
is likely to be at least equal to that of the Sun's asteroid belt, and perhaps
much larger. We report abundances of a suite of 8 elements detected in the
little studied star G241-6 that we find to be among the most heavily polluted
of all moderately bright white dwarfs.
