Rubin Observatory Spots a 'Once-in-a-Generation' Dwarf Planet Candidate
The Vera C. Rubin Observatory has identified 2026 ED138, a distant icy body 46 astronomical units from the Sun estimated at up to 1,500 km across, as a potential sixth dwarf planet in our solar system.
Astronomers using the Simonyi Survey Telescope at NSF–DOE Vera C. Rubin Observatory in Chile have discovered 2026 ED138, a trans-Neptunian object that could become the sixth officially recognised dwarf planet. The body orbits approximately 46 astronomical units from the Sun — further out than Pluto's average of 40 AU — and is estimated to measure between 600 and 1,500 kilometres in diameter. Senior astrophysicist Matthew Holman described his reaction as 'excited disbelief,' while University of Washington astronomy professor Mario Jurić called it 'something that happens maybe once in a generation.' The object was first spotted in the new survey data, but archival records trace it back to 2016, giving scientists more than a decade of orbital observations to refine its path. If confirmed by the International Astronomical Union, 2026 ED138 would join Pluto, Ceres, Eris, Haumea, and Makemake as recognised dwarf planets. The discovery showcases Rubin Observatory's unique ability to detect faint, slow-moving outer-solar-system objects that were previously hidden against star-dense regions of the sky, and is seen as a preview of the thousands of new objects the observatory is expected to catalogue over its decade-long Legacy Survey of Space and Time.
