Characterization of HD 206893 B from Near- to Thermal-infrared

HD 206893 B is a brown-dwarf companion orbiting inside the debris disk of its host star. We detect the brown dwarf in the Ms band using the Keck/NIRC2 instrument and vortex coronagraph. We measure its magnitude to be Ms=12.97_-0.11^0.10 . It is at an angular separation of 0``22 \ensuremath± 0''03, and a position angle of 39.6° \ensuremath± 5.4° east of north. Using this Ms-band measurement and the system age, we use three evolutionary models to estimate the mass to be 12-78 M_Jup. We analyze the atmospheric properties from 1-5 \ensuremathμm using a grid of simulated atmospheric models. We find that a sedimentation flux f_sed value \raisebox-0.5ex~0.2 provides the best fit to the data, suggesting high vertically extended clouds. This may be indicative of high-altitude grains or a circumplanetary disk. Our model radii and luminosities for the companion find the best fits are ages of <100 Myr and masses