2020AJ....159..116Z

We report the discovery and the analysis of the short (t_E< 5 days) planetary microlensing event, OGLE-2015-BLG-1771. 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 ∼ 5.4 x 10^–3, 4.5 x 10^–3 and 4.5 x 10^–2, respectively. The first model is the best-fit model, while the second model is disfavored by Δχ² ∼ 3. The last model is strongly disfavored by Δχ² ∼ 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. The source-lens relative proper motion is µ_rel ∼ 9 mas yr^–1, so the source and lens could be resolved by current adaptive-optics instruments in 2020 if the lens is luminous.