The NSF–DOE Vera C. Rubin Observatory has identified a moving object beyond Pluto that could rank among the largest dwarf planet candidates found so far, though its classification remains unconfirmed, Rubin Observatory said Tuesday.
The International Astronomical Union’s Minor Planet Center assigned the object the provisional designation 2026 ED138, shortened to ED138. If confirmed as a dwarf planet, it would join the five recognized dwarf planets: Pluto, Ceres, Eris, Haumea and Makemake.
ED138 was detected in a star-rich region near the plane of the Milky Way. Rubin Observatory said the crowded background likely helped keep the object from being discovered earlier. Its monitoring and data analysis identified movement among the many stars in that area.
The observatory’s design helped enable the discovery. Its camera is the largest ever created, and its imaging system is built to capture changes across the southern hemisphere sky. Edward Ajhar, the National Science Foundation’s program director for Rubin Observatory, said the facility can reveal movement among a vast number of objects and phenomena.
Scientists can now use other observatories to make follow-up observations and learn more about ED138. Those observations may help establish the object’s nature and whether it qualifies as a dwarf planet.
The observatory is jointly funded by the National Science Foundation (NSF) and the U.S. Department of Energy’s (DOE) Office of Science. Rubin also submitted April observations covering more than 11,000 newly identified asteroids, the NSF report said.
