  The destiny of planetary systems through the late evolution of their host
stars is very uncertain. We report a metal-rich gas disk around a moderately
hot and young white dwarf. A dynamical model of the double-peaked emission
lines constrains the outer disk radius to just 1.2 solar radii. The likely
origin of the disk is a tidally disrupted asteroid, which has been destabilised
from its initial orbit at a distance of more than 1000 solar radii by the
interaction with a relatively massive planetesimal object or a planet. The
white dwarf mass of 0.77 solar masses implies that planetary systems may form
around high-mass stars.
