  A significant fraction of main sequence stars observed interferometrically in
the near infrared have slightly extended components that have been attributed
to very hot dust. To match the spectrum appears to require the presence of
large numbers of very small (< 200 nm in radius) dust grains. However,
particularly for the hotter stars, it has been unclear how such grains can be
retained close to the star against radiation pressure force. We find that the
expected weak stellar magnetic fields are sufficient to trap nm-sized dust
grains in epicyclic orbits for a few weeks or longer, sufficient to account for
the hot excess emission. Our models provide a natural explanation for the
requirement that the hot excess dust grains be smaller than 200 nm. They also
suggest that magnetic trapping is more effective for rapidly rotating stars,
consistent with the average vsini measurements of stars with hot excesses being
larger (at about 2 sigma) than those for stars without such excesses.
