Using a technique plucked from the toolbox of Einstein’s general relativity, astronomers have uncovered a giant planet circling a sunlike star about 25,000 light-years from Earth in the constellation Sagittarius. Though the planet is probably too large to support life, it orbits in or near the star’s habitable zone — a distance that could enable liquid water to puddle on the planet’s moons, if it has any.
MOA-2011-BLG-293Lb is the first habitable-zone planet detected via gravitational microlensing, in which the gravitational influence of a star and its planets slightly bends the light of a more distant object. It is also the first planetary system discovered within the bulge of stars concentrated in the center of the Milky Way.
An international team reported the results in a paper posted October 14 on arXiv.org.