New Dwarf Planet Candidate in Our Solar System

NSF-DOE Vera C. Rubin Observatory has identified 2026 ED138, a distant object beyond Pluto, as a candidate dwarf planet. Rubin team member Matthew Holman found it by using a search algorithm to match detections of moving objects across the observatory’s data. Follow-up searches uncovered 20 additional Rubin observations: the telescope recorded the object 30 times on 20 nights between March 4 and July 11, 2026. Archival images from the Dark Energy Camera, located through the Asteroid Institute’s ADAM Precovery service, extended the record back to 2016, allowing researchers to trace more than a decade of its orbit.

ED138 is about 46 astronomical units from the Sun, compared with Pluto’s average distance of 40, and its orbit is tilted almost 25 degrees from the Solar System’s plane. That inclination identifies it as a “hot-classical” trans-Neptunian object and suggests gravitational interactions with Neptune shifted it from its original path. Researchers estimate its diameter at 600 to 1,500 kilometers based on its distance, brightness, and assumed surface reflectivity. A dwarf planet must be large enough for its gravity to make it roughly round, so ED138 remains a candidate pending further assessment. If confirmed, it could rank among the largest and brightest objects found in this distant region, and help scientists investigate the Solar System’s formation and evolution.