A newly discovered object beyond Pluto may be one of the largest dwarf planets found in the outer solar system, researchers say. The candidate, named 2026 ED138, is estimated to be between 370 and 930 miles wide.
The discovery was announced Oct. 27 and came from observations made by the Vera C. Rubin Observatory in Chile. The facility began a decade-long survey of the sky in June 2026, using a large digital camera to search for objects that have so far gone unnoticed.
Astronomer Matthew Holman found ED138 on Oct. 13 while reviewing data collected earlier in the year. He was using search software he developed with colleague Kevin Napier. The object’s brightness and distance suggested it was unusually large, but Holman said he initially wondered whether there had been a mistake in the data or the software.
ED138 is about 4.3 billion miles from the sun, farther away than Pluto, which averages roughly 3.7 billion miles from the sun. It is classified as a trans-Neptunian object because it orbits beyond Neptune.
Researchers say ED138 may have escaped earlier detection because it lies in a crowded area of the sky near the Milky Way. The Rubin Observatory’s repeated observations of the southern sky, along with computer algorithms that pick out moving objects among millions of points of light, helped bring it into view.
More observations are needed to establish the object’s precise size and determine whether it meets the criteria for a dwarf planet. If confirmed, it would join a small group of known dwarf planets. These bodies orbit the sun and are nearly round, but have not cleared other objects from their orbital paths.
Pluto was classified as the solar system’s ninth planet after its discovery in 1930. In 2006, it was reclassified as a dwarf planet. Scientists hope Rubin’s decade-long survey will reveal other distant objects that earlier searches may have missed.
Other recent findings have also offered clues about the solar system’s history. Researchers reported earlier this year that a meteorite which broke through the roof of a New Jersey home in 2024 contained chemical building blocks of life. The rock was more than 4.5 billion years old and was among the rarest meteorites recovered.
