I-band light curves of OGLE-2015-BLG-1771Lb

The event was discovered by the Optical Gravitational Lensing Experiment, and the planetary anomaly (at I~19) was captured by The Korea Microlensing Telescope Network. The event has three surviving planetary models that explain the observed light curves, with planet-host mass ratio q~5.4x10^-3^, 4.5x10^-3^ and 4.5x10^-2^, respectively.

The first model is the best-fit model, while the second model is disfavored by {Delta}_{chi}^2^_~3. The last model is strongly disfavored by {Delta}_{chi}^2^_~15 but not ruled out. A Bayesian analysis using a Galactic model indicates that the first two models are probably composed of a Saturn-mass planet orbiting a late M dwarf, while the third one could consist of a super-Jovian planet and a mid-mass brown dwarf.