Planet: MOA-2012-BLG-0006L b
Discovered by: R. Poleski and the OGLE microlensing collaboration
Date: September 15, 2017
Key Facts: This new discovery is so massive, astronomers can't say for certain whether it's a planet or a small failed star. The probable gas giant is a world of extremes: over eight times more massive than Jupiter, it also takes about 32 years to complete one orbit around its red star.
Our take: Microlensing helps us find planets toward the bright center of the Milky Way that otherwise we couldn't see. In gravitational microlensing, light from a distant star is bent and focused by gravity as a planet passes between the star and Earth. The catch is that we only get to view a microlensing planet once, before it fades back into the black of space. We're not sure how a planet the size of this gas giant was formed, but further microlensing studies could help us find clues to the existence of other planets like it.
Read more: NASA Exoplanet Archive
Paper: "A companion on the planet/brown dwarf mass boundary on a wide orbit discovered by gravitational microlensing"