OGLE-2016-BLG-0693LB: Probing the Brown Dwarf Desert with Microlensing

We present an analysis of microlensing event OGLE-2016-BLG-0693, based on the survey-only microlensing observations by the OGLE and KMTNet groups. In order to analyze the light curve, we consider the effects of parallax, orbital motion, and baseline slope, and also refine the result using a Galactic model prior. From the microlensing analysis, we find that the event is a binary composed of a low-mass brown dwarf ( ) companion and a K- or G-dwarf host, which lies at a distance of 5.0 0.6 kpc toward the Galactic bulge. The projected separation between the brown dwarf and its host star is less than ∼5 au, thus it is likely that the brown dwarf companion is located in the brown dwarf desert.