Scientists Spot Potential New Dwarf Planet Beyond Pluto
Researchers using the Vera C. Rubin Observatory have identified an icy object, 2026 ED138, that may qualify as a dwarf planet, pending further observations.
Scientists using the Vera C. Rubin Observatory in Chile have detected an icy body, designated 2026 ED138, orbiting far beyond Pluto. The object is estimated to be between 600 and 1,500 km in diameter and resides about 46 astronomical units from the Sun, compared with Pluto’s average distance of roughly 40 astronomical units.
The discovery, announced at a scientific meeting in Spokane, Washington, adds a candidate to the International Astronomical Union’s list of recognized dwarf planets, which currently includes Pluto, Eris, Haumea, Makemake and Ceres. If confirmed, 2026 ED138 would rank among the larger dwarf planets.
"For me, what this demonstrates is that many exciting discoveries remain to be made with the Rubin Observatory and other telescopes," said astrophysicist Matt Holman of the Center for Astrophysics, Harvard & Smithsonian, who first identified the object.
"The main thing we need to do is to establish the physical size of 2026 ED138," Holman added. He explained that observations at longer wavelengths, such as those possible with the Atacama Large Millimeter/submillimeter Array (ALMA), can help determine the object's size by detecting its own emitted light rather than reflected sunlight.
Further measurements are required to confirm the object's mass and shape, criteria needed for dwarf-planet classification.