OGLE-2005-BLG-071Lb is a planet discovered by the Optical Gravitational Lensing Experiment (OGLE) and others in 2005, using gravitational microlensing.^[1] According to the best fit model, it has about 3.5 times the mass of Jupiter and a projected separation of 3.6 astronomical units from the star. This would result in an effective temperature around 50 K, similar to that of Neptune. However, an alternative model which gives a slightly lower mass of 3.3 times that of Jupiter and a projected separation of 2.1 AU is only slightly less likely. It may be the most massive planet currently known around a red dwarf star (though only lower limits are known for those planets detected by the radial velocity method).^[2]