OGLE-2018-BLG-0677Lb: A Super-Earth Near the Galactic Bulge

We report the analysis of the microlensing event OGLE-2018-BLG-0677. A small feature in the light curve of the event leads to the discovery that the lens is a star-planet system. Although there are two degenerate solutions that could not be distinguished for this event, both lead to a similar planet-host mass ratio. We perform a Bayesian analysis based on a Galactic model to obtain the properties of the system and find that the planet corresponds to a super-Earth/sub-Neptune with a mass of = -+Mplanet 3.96 2.66MA5.88. The host star has a mass of = M 0.12+ M host 0.080.14.. The projected separation for the inner and outer solutions are 0.63+ 0.170.20 au and 0.72+ 0.190.23 au respectively. At Dc2 = c2 (1L1S) - c2 (2L1S) = 46, this is by far the lowest..2 for any securely detected microlensing planet to date, a feature that is closely connected to the fact that it is detected primarily via a "dip" rather than a "bump."