Vera Rubin Observatory Spots Potential Sixth Dwarf Planet Beyond Pluto
The Vera C. Rubin Observatory has identified 2026 ED138, a trans-Neptunian object 46 times farther from the Sun than Earth, as a candidate for our solar system's sixth dwarf planet. The object measures between 600 and 1,500 km across.
Astronomers announced on Tuesday, October 27, 2026, that the Vera C. Rubin Observatory has found a new dwarf planet candidate: 2026 ED138, a large body orbiting beyond Neptune at roughly 46 astronomical units from the Sun — even more remote than Pluto, which sits at about 40 AU. The object was identified by Matthew Holman and Kevin Napier of the Center for Astrophysics at Harvard & Smithsonian, who ran billions of pieces of Rubin survey data through a purpose-built search algorithm. Holman and his colleague Mario Jurić of the University of Washington then verified the discovery by locating 30 additional Rubin observations of 2026 ED138, all dating from between March and July 2026. Using other observation tools, the pair also traced sightings of the object back to 2016. The object's orbit is tilted about 25 degrees off the solar system's plane, a feature that may be linked to Neptune's gravitational pull. Initial size estimates put its diameter between 600 and 1,500 kilometres (373 to 932 miles), ranking it among the largest dwarf planet candidates ever detected and potentially making it the sixth member of that class alongside Pluto, Ceres, Eris, Haumea, and Makemake. Formal confirmation requires further observations to establish that 2026 ED138 has enough mass to pull itself into a spherical shape — the key criterion for dwarf planet status. The discovery was made possible by Rubin's powerful instruments and its ability to pick out faint objects in regions of sky crowded with starlight that had long hidden the object from view.
