Astronomers have discovered a potential new dwarf planet beyond Pluto using data collected by the Vera C. Rubin Observatory in Chile. The icy object, provisionally designated 2026 ED138, could become one of the largest dwarf planets identified in the outer solar system if further observations confirm its classification.
Scientists estimate that 2026 ED138 is between approximately 600 and 1,500 kilometres in diameter. It currently orbits about 46 times farther from the Sun than Earth, placing it beyond Pluto’s average orbital distance of roughly 40 astronomical units.
The object was identified by Matthew Holman of the Center for Astrophysics | Harvard & Smithsonian while analysing data collected by the Rubin Observatory. Researchers subsequently located additional observations, allowing them to trace the object’s orbital path over several years.
The discovery is particularly significant because 2026 ED138 was detected in a crowded region of the sky near the plane of the Milky Way, where countless stars can make distant objects difficult to identify. The observatory’s advanced imaging capabilities and data-processing methods helped scientists distinguish the object from the surrounding celestial sources.
However, 2026 ED138 has not yet been officially confirmed as a dwarf planet. Scientists need additional observations to determine its precise size and establish whether its gravity is sufficient to give it a nearly spherical shape. Infrared observations could help researchers better understand its physical characteristics.
If confirmed, the object could join the five dwarf planets currently recognised by the International Astronomical Union: Pluto, Ceres, Eris, Haumea and Makemake.
The discovery also highlights the potential of the Vera C. Rubin Observatory to reveal previously unidentified objects in the distant solar system. As astronomers continue analysing its observations, researchers hope to gain a better understanding of the solar system’s formation and the icy worlds beyond Neptune.
