New dwarf planet candidate discovered by NSF–DOE Rubin Observatory

NSF–DOE Vera C. Rubin Observatory has found a large object that scientists have identified as a possible dwarf planet. A preliminary data analysis shows that the object is orbiting in the outer reaches of the solar system beyond Pluto and may be one of the largest dwarf planet candidates ever found. If confirmed, the object would join the five other known dwarf planets: Pluto, Ceres, Eris, Haumea, and Makemake. 

Rubin Observatory is jointly funded by the U.S. National Science Foundation and U.S. Department of Energy's Office of Science. The discovery was enabled by Rubin's unparalleled speed and its enormous camera, the largest ever created, allowing it to precisely capture every visible change in the southern hemisphere sky. The International Astronomical Union Minor Planet Center has given the newly discovered object the provisional designation ED138. 

ED138 was found in a region of sky close to the plane of the Milky Way, a region visually filled with millions of stars, which is likely why it was not discovered until now. Rubin Observatory's regular monitoring and powerful data algorithms allowed scientists to spot ED138 moving within the crowded field. 

"Rubin Observatory's superpower is the ability to clearly capture movement and change among a vast number of objects and phenomena that humans have never seen before," says Edward Ajhar, NSF Program Director for Rubin Observatory. "That power greatly extends our ability to reveal and understand new things about our solar system, the Milky Way, and billions of other galaxies across the universe."

Scientists using other observatories can now make follow-up observations of ED138 to uncover more information about its nature. The public, including students and teachers, can learn more about this discovery on Orbitviewer, an interactive web-based app that provides an intuitive way to explore objects in the solar system. 

ED138 is one of many solar system objects discovered by Rubin this year. In April, Rubin submitted observations of over 11,000 new asteroids. 

"Rubin Observatory’s unique strengths make it an incredible tool for investigating a wide range of astrophysical phenomena, from dark energy to the discovery of this dwarf planet candidate," says Kathy Turner, Department of Energy Program Manager for Rubin Observatory.