  We report preliminary results from our search for massive giant planets (6-12
Jupiter masses) around the known seven single white dwarfs in the Hyades
cluster at sub-arcsec separations. At an age of 625 Myr, the white dwarfs had
progenitor masses of about 3 solar masses, and massive gaseous giant planets
should have formed in the massive circumstellar disks around these ex-Herbig A0
stars, probably at orbital separations similar or slightly larger than that of
Jupiter. Such planets would have survived the post-Main-Sequence mass loss of
the parent star and would have migrated outward adiabatically to a distance of
about 25 AU. At the distance of the Hyades (45 pc) this corresponds to an
angular separation of 0.5 arcsec. J and H magnitudes of these giants are in the
range of 20.5-23.3 mag, which can be resolved with NICMOS. The achieved
sensitivities and contrast ratios agree well with simulations. Preliminary
evaluation of the NICMOS data set did not reveal any evidence for neither
planetary mass companions with masses down to about 10 Jupiter masses nor brown
dwarfs around any of the seven white dwarfs for separations larger than 0.5
arcsec.
