Overview
- The object was first flagged by Matthew Holman on Oct. 13 while he ran Rubin data through search code he co‑developed, and teams found Rubin detections from March–July 2026 plus archival images back to 2016 that give a decade‑long orbital arc.
- Initial brightness and distance imply a diameter between about 600 and 1,500 kilometers but that range depends on surface reflectivity so its physical size is not yet measured.
- Orbit fits place 2026 ED138 roughly 46 astronomical units from the Sun on a path tilted about 25 degrees to the solar system plane.
- Researchers plan targeted follow‑ups over coming months including stellar occultations, thermal or millimeter observations with facilities like ALMA or infrared measurements with JWST, and light‑curve studies to test whether the body is round enough to qualify as a dwarf planet.
- If confirmed, the find would be the largest trans‑Neptunian discovery in about 20 years and highlights the Vera C. Rubin Observatory’s repeated deep imaging and automated search tools that can reveal rare, hidden worlds in the southern sky.