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 ( OGLE ) , and the planetary anomaly ( at I \sim 19 ) was captured by The Korea Microlensing Telescope Network ( KMTNet ) .
The event has three surviving planetary models that explain the observed light curves , with planet-host mass ratio q \sim 5.4 \times 10 ^ { -3 } , 4.5 \times 10 ^ { -3 } and 4.5 \times 10 ^ { -2 } , respectively .
The first model is the best-fit model , while the second model is disfavored by \Delta \chi ^ { 2 } \sim 3 .
The last model is strongly disfavored by \Delta \chi ^ { 2 } \sim 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 \mu _ { rel } \sim 9 ~ { } { mas yr ^ { -1 } } , so the source and lens could be resolved by current adaptive-optics ( AO ) instruments in 2021 if the lens is luminous .