OGLE-2018-BLG-0677Lb: A Super-Earth Near the Galactic Bulge
Antonio Herrera-Martín, M. D. Albrow, A. Udalski, A. Gould, Y.-H. Ryu, J. C. Yee, S.-J. Chung, C. Han, K.-H. Hwang, Y. K. Jung, C.-U. Lee, I.-G. Shin, Y. Shvartzvald, W. Zang, S.-M. Cha, D.-J. Kim, H.-W. Kim, S.-L. Kim, D.-J. Lee, Y. Lee, B.-G. Park, R. W. Pogge, M. K. Szymański, P. Mróz, J. Skowron, R. Poleski, I. Soszyński, S. Kozłowski, P. Pietrukowicz, K. Ulaczyk, K. Rybicki, P. Iwanek, M. Wrona
Abstract
Abstract 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 . The host star has a mass of . The projected separation for the inner and outer solutions are au and au respectively. At , this is by far the lowest Δ χ 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.”