Radial velocity ( RV ) searches for exoplanets have surveyed many of the nearest and brightest stars for long-term velocity variations indicative of a companion body .
Such surveys often detect high-amplitude velocity signatures of objects that lie outside the planetary mass regime , most commonly those of a low-mass star .
Such stellar companions are frequently discarded as false-alarms to the main science goals of the survey , but high-resolution imaging techniques can be employed to either directly detect or place significant constraints on the nature of the companion object .
Here , we present the discovery of a compact companion to the nearby star HD 118475 .
Our Anglo-Australian Telescope ( AAT ) RV data allow the extraction of the full Keplerian orbit of the companion , found to have a minimum mass of 0.445 M _ { \odot } .
Follow-up speckle imaging observations at the predicted time of maximum angular separation rule out a main-sequence star as the source of the RV signature at the 3.3 \sigma significance level , implying that the companion must be a low-luminosity compact object , most likely a white dwarf .
We provide an isochrone analysis combined with our data that constrain the possible inclinations of the binary orbit .
We discuss the eccentric orbit of the companion in the context of tidal circularization timescales and show that non-circular orbit was likely inherited from the progenitor .
Finally , we emphasize the need for utilizing such an observation method to further understand the demographics of white dwarf companions around nearby stars .