We present new observations of the faint “ Sirius-like ” companion discovered to orbit HD 114174 .
Previous attempts to image HD 114174 B at mid-infrared wavelengths using NIRC2 at Keck have resulted in a non-detection .
Our new L ’ -band observations taken with the Large Binocular Telescope and LMIRCam recover the companion ( \Delta L = 10.15 \pm 0.15 mag , \rho = 0.675 ” \pm 0.016 ” ) with a high signal-to-noise ratio ( 10 \sigma ) .
This measurement represents the deepest L ’ high-contrast imaging detection at sub-arcsecond separations to date , including extrasolar planets .
We confirm that HD 114174 B has near-infrared colors consistent with the interpretation of a cool white dwarf ( J - L ^ { \prime } = 0.76 \pm 0.19 mag , K - L ^ { \prime } = 0.64 \pm 0.20 ) .
New model fits to the object ’ s spectral energy distribution indicate a temperature T _ { eff } = 4260 \pm 360 K , surface gravity log g = 7.94 \pm 0.03 , a cooling age t _ { c } \approx 7.8 Gyr , and mass M = 0.54 \pm 0.01 M _ { \odot } .
We find that the cooling age given by theoretical atmospheric models do not agree with the age of HD 114174 A derived from both isochronological and gyrochronological analyses .
We speculate on possible scenarios to explain the apparent age discrepancy between the primary and secondary .
HD 114174 B is a nearby benchmark white dwarf that will ultimately enable a dynamical mass estimate through continued Doppler and astrometric monitoring .
Efforts to characterize its physical properties in detail will test theoretical atmospheric models and improve our understanding of white dwarf evolution , cooling , and progenitor masses .