Presentation #408.02 in the session Exoplanet Direct Imaging — iPoster Session.
Brown Dwarfs (BD) with well-measured masses, age and luminosities are important benchmark objects to test BD formation and evolutionary models. We present the direct imaging discovery of a substellar companion to HD 176535A, a Sun-like K3.5 (V) star aged 5.04 ± 1.45 Gyrs at a distance of 37.0 ± 0.024 pc. The radial velocity of the star is from the High Accuracy velocity Planet Searcher (HARPS) spectrograph based on 11 years of monitoring. Our high-contrast imaging observation with the Keck/NIRC2 coronagraph revealed a companion (L'p = 13.39 ± 0.14 mag) at 0.35” or 10.98 AU. We perform a joint fit of the archival RVs, our single-epoch relative astrometry, and complementary absolute astrometry from Hipparcos and Gaia EDR3 catalog of accelerations, using an open-source orbit fitting python code orvara. We obtain a precise dynamical mass of 65.7-1.6+2.0 MJup for the high-mass brown dwarf HD 176535B. We conclude that HD 176535B will be a great candidate for more future high-contrast imaging observations with instruments such as CHARIS, which will further help us to refine its orbital parameters and atmospheric characterizations.