We present the analysis of microlensing event MOA-2010-BLG-117 , and show that the light curve can only be explained by the gravitational lensing of a binary source star system by a star with a Jupiter mass ratio planet .
It was necessary to modify standard microlensing modeling methods to find the correct light curve solution for this binary-source , binary-lens event .
We are able to measure a strong microlensing parallax signal , which yields the masses of the host star , M _ { * } = 0.58 \pm 0.11 M _ { \odot } , and planet m _ { p } = 0.54 \pm 0.10 M _ { Jup } at a projected star-planet separation of a _ { \perp } = 2.42 \pm 0.26 AU , corresponding to a semi-major axis of a = 2.9 { +1.6 \atop - 0.6 } AU .
Thus , the system resembles a half-scale model of the Sun-Jupiter system with a half-Jupiter mass planet orbiting a half-solar mass star at very roughly half of Jupiter ’ s orbital distance from the Sun .
The source stars are slightly evolved , and by requiring them to lie on the same isochrone , we can constrain the source to lie in the near side of the bulge at a distance of D _ { S } = 6.9 \pm 0.7 kpc , which implies a distance to the planetary lens system of D _ { L } = 3.5 \pm 0.4 kpc .
The ability to model unusual planetary microlensing events , like this one , will be necessary to extract precise statistical information from the planned large exoplanet microlensing surveys , such as the WFIRST microlensing survey .