MOA Data Reveal a New Mass, Distance, and Relative Proper Motion for Planetary System OGLE-2015-BLG-0954L

Abstract

We present the MOA Collaboration light-curve data for the planetary microlensing event OGLE-2015-BLG-0954, which was previously announced in a paper by the KMTNet and OGLE Collaborations. The MOA data cover the caustic exit, which was not covered by the KMTNet or Optical Gravitational Lensing Experiment (OGLE) data, and they provide a more reliable measurement of the finite source effect. The MOA data also provide a new source color measurement that reveals a lens-source relative proper motion of μ rel  = 11.8 ± 0.8 mas yr −1 , which compares to the value of μ rel  = 18.4 ± 1.7 mas yr −1 reported in the KMTNet-OGLE paper. This new MOA value for μ rel has an a priori probability that is a factor of ≳100 times larger than the previous value, and it does not require a lens system distance of D L  < 1 kpc. Based on the corrected source color, we find that the lens system consists of a planet of mass orbiting a star at an orbital separation of and a distance of .