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 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 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 $\hat{I}{¼}_{\mathrm{rel}}=11.8\pm 0.8$mas/yr, which compares to the value of $\hat{I}{¼}_{\mathrm{rel}}=18.4\pm 1.7$mas/yr reported in the KMTNet-OGLE paper. This new MOA value for $\hat{I}{¼}_{\mathrm{rel}}$ has an a priori probability that is a factor of $\sim 100$ 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 $3.4_{-1.6}^{+3.7}{M}_{\mathrm{Jup}}$ orbiting a $0.30_{-0.14}^{+0.34}{M}_{\odot }$ star at an orbital separation of $2.1_{-1.0}^{+2.2}$AU and a distance of $1.2_{-0.5}^{+1.1}$kpc.

18 pages, 2 figures, submitted to AAS Journals