Overview
- Astronomers announced that the Vera C. Rubin Observatory team identified a new trans‑Neptunian object provisionally designated 2026 ED138 and reported its discovery to the Minor Planet Center.
- Precovery images extending back to 2016 plus roughly 30 Rubin detections from March–July 2026 establish a well‑constrained orbit that ranges about 36.86–49.04 AU from the Sun and has a ~281‑year period.
- Initial brightness and distance give a broad diameter estimate of about 600–1,500 kilometers, a range that makes ED138 a strong dwarf‑planet candidate but leaves size uncertain because surface reflectivity is unknown.
- Matthew Holman first flagged the object after running Rubin data through search software on Oct. 13, and the team now plans follow‑up work — thermal infrared observations, occultation campaigns, and light‑curve measurements — to measure its true size and shape.
- The find illustrates Rubin’s LSST power to reveal faint, slow movers hidden in crowded star fields and suggests the 10‑year survey will rapidly expand the inventory of large outer‑solar‑system bodies and inform models of planetary dynamics.