THE TRENDS HIGH-CONTRAST IMAGING SURVEY. III. A FAINT WHITE DWARF COMPANION ORBITING HD 114174.

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 mag (contrast of 5 × 10-5) fainter than its host in the K-band, requiring aggressive point-spread function subtraction to identify. Our astrometric time baseline of 1.4 yr demonstrates physical association through common proper motion. We find that the companion has absolute magnitude, MJ = 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 0.260±0.010Mʘ. 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 = 8200 ± 4000 K, surface gravity log g = 8.90 ± 0.02, and cooling age of tc ≈ 3.4 Gyr, which is consistent with the 4.7+2.3 -2.6 Gyr host star isochronal age estimate. HD 114174 B is a benchmark object located only 26.14 ± 0.37 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. [ABSTRACT FROM AUTHOR]