  A detailed analysis of 32 of the 38 halo white dwarf candidates identified by
Oppenheimer et al. is presented, based on model atmosphere fits to observed
energy distributions built from optical BVRI and infrared JHK CCD photometry.
Effective temperatures and atmospheric compositions are determined for all
objects, as well as masses and cooling ages when trigonometric parallax
measurements are available. This sample is combined with that of other halo
white dwarf candidates and disk white dwarfs to study the nature of these
objects in terms of reduced proper motion diagrams, tangential velocities, and
stellar ages. We reaffirm the conclusions of an earlier analysis based on
photographic magnitudes of the same sample that total stellar ages must be
derived in order to associate a white dwarf with the old halo population, and
that this can only be accomplished through precise mass and distance
determinations.
