OGLE/KMTnet VI bands photometry of OGLE-2019-BLG-0551

Here, we report the discovery of another strong free-floating planet candidate, which was found from the analysis of the gravitational microlensing event OGLE-2019-BLG-0551. The light curve of the event is characterized by a very short duration (<~3days) and a very small amplitude (<~0.1mag).

From modeling of the light curve, we find that the Einstein timescale, t_E_=0.381{+/-}0.017day, is much shorter, and the angular Einstein radius, {theta}_E_=4.35{+/-}0.34{mu}mas, is much smaller than those of typical lensing events produced by stellar-mass lenses (t_E_~20days, {theta}_E_~0.3mas), indicating that the lens is very likely to be a planetary-mass object. We conduct an extensive search for possible signatures of a companion star in the light curve of the event, finding no significant evidence for the putative host star.