  A young and undermassive white dwarf has been identified as the possible
companion to the millisecond pulsar PSR B1620-26 in Messier 4. This association
is important as it then helps constrain the mass of the third body in the
system to be of order a few times that of Jupiter. The presence of this planet
in M4 has critical implications for planetary formation mechanisms in
metal-poor environments such as globular clusters and the early Universe. The
identification of the white dwarf is purely via the agreement in position
between it and the pulsar and was limited by the accuracy of the pointing of
HST which is +/-0.7 arcsec. We have redetermined the position of the white
dwarf using ground-based data tied to USNOB-1.0 and find that the pulsar and
white dwarf are now coincident to within 0.12 +/- 0.13 arcsec further
strengthening the case for association between the two. We have also attempted
to improve the proper motion measurement of the white dwarf by a maximum
likelihood analysis of the stellar positions measured over a baseline of 5
years. While the errors are reduced by almost a factor of 6 from our previous
work, we still have not resolved the cluster's intrinsic dispersion in proper
motion. Thus the proper motion of the white dwarf with respect to the cluster
itself is still not known although it is very small and is within 2-sigma of
that of the cluster internal dispersion.
