Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing.

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of 0.71 and 0.27 times the mass of Jupiter and orbital separations of 2.3 and 4.6 astronomical units orbiting a primary star of mass 0.50 solar mass at a distance of 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common. [ABSTRACT FROM AUTHOR]