Overview
- Researchers report in Science that they directly measured both the mass and distance of a free-floating planet for the first time.
- The object is about 22% of Jupiter’s mass—roughly Saturn-mass—and lies near the Galactic bulge at around 3,000 parsecs, just under 10,000 light-years away.
- The microlensing event, cataloged as KMT-2024-BLG-0792 and OGLE-2024-BLG-0516, was captured from ground networks and by ESA’s Gaia at L2, enabling a precise microlens parallax measurement.
- Its relatively low mass points to formation within a planetary system followed by dynamical ejection rather than star-like, isolated formation, helping fill the so-called Einstein desert in the mass distribution.
- Astronomers expect upcoming wide-field surveys, notably NASA’s Nancy Grace Roman Space Telescope slated for 2027, to greatly expand the sample and enable statistical studies of unbound planets.