OGLE-2018-BLG-0584 and KMT-2018-BLG-2119: Two microlensing events with two lens masses and two source stars

Aims. We conducted a systematic investigation of the microlensing data collected during the previous observation seasons for the purpose of re-analyzing anomalous lensing events with no suggested plausible models.Methods. We found that two anomalous lensing events, OGLE-2018-BLG-0584 and KMT-2018-BLG-2119, cannot be explained with the usual models based on either a binary-lens single-source (2L1S) or a single-lens binary-source (1L2S) interpretation. We tested the feasibility of explaining the light curves of the events with more sophisticated models by adding either an extra lens (3L1S model) or a source (2L2S model) component to the 2L1S lens system configuration.Results. We find that a 2L2S interpretation explains the light curves of both events well and that for each event there are a pair of solutions resulting from the close and wide degeneracy. For the event OGLE-2018-BLG-0584, the source is a binary composed of two K-type stars and the lens is a binary composed of two M dwarfs. For KMT-2018-BLG-2119, the source is a binary composed of two dwarfs of G and K spectral types and the lens is a binary composed of a low-mass M dwarf and a brown dwarf.

Automated summary

In this study, we conducted a systematic investigation of previous observation data to re-analyze anomalous lensing events without plausible models. We found that usual models based on either a binary-lens single-source (2L1S) or a single-lens binary-source (1L2S) interpretation cannot explain two anomalous lensing events. By adding extra lens or source components to the lens system configuration, we tested the feasibility of explaining the events with more sophisticated models. The results show that a 2L2S interpretation explains the light curves of both events well, and there are pairs of solutions due to close and wide degeneracy.