  The nearby Sun-like star HD 114174 exhibits a strong and persistent Doppler
acceleration indicating the presence of an unseen distant companion. We have
acquired high-contrast imaging observations of this star using NIRC2 at Keck
and report the direct detection of the body responsible for causing the
"trend". HD 114174 B has a projected separation of 692+/-9 mas (18.1 AU) and is
10.75+/-0.12 magnitudes (contrast of 5x10{-5}) fainter than its host in the
K-band, requiring aggressive point-spread function subtraction to identify. Our
astrometric time baseline of 1.4 years demonstrates physical association
through common proper motion. We find that the companion has absolute
magnitude, M_J=13.97+/-0.11, and colors, J-K= 0.12+/-0.16 mag. These
characteristics are consistent with an ~T3 dwarf, initially leading us to
believe that HD 114174 B was a substellar object. However, a dynamical analysis
that combines radial velocity measurements with available imaging data
indicates a minimum mass of m=0.260+/-0.010Msun. We conclude that HD 114174 B
must be a white dwarf. Assuming a hydrogen-rich composition, atmospheric and
evolutionary model fits yield an effective temperature Teff = 8160+/-4000 K,
surface gravity log g=8.90+/-0.02, and cooling age of t_c=3.4 Gyr, which is
consistent with the 4.7+/-2.4 Gyr host star isochronal age estimate. HD 114174
B is a benchmark object located only d=26.1 pc from the Sun. It may be studied
at a level of detail comparable to Sirius and Procyon, and used to understand
the link between the mass of white dwarf remnants with that of their
progenitors.
