New dwarf planet candidate ED138 discovered beyond Pluto

Astronomers have identified a potential new dwarf planet candidate, ED138, located beyond Pluto's orbit. The discovery was made using data from the Vera C. Rubin Observatory, a facility in Chile that began its 10-year survey in June 2026.

ED138, estimated to be between 370 and 930 miles in diameter, was spotted by astronomer Matthew Holman using software he developed with colleague Kevin Napier. The object was found in data collected earlier this year.

Scientists classify ED138 as a trans-Neptunian object, meaning it orbits the sun beyond Neptune. It is currently located about 4.3 billion miles from the sun, farther than Pluto, which averages 3.7 billion miles from the sun.

The Rubin Observatory's advanced digital camera and powerful algorithms allowed researchers to detect ED138 in a crowded region of the sky near the Milky Way, where earlier telescopes struggled to find it. The observatory is jointly funded by the U.S. National Science Foundation and the Department of Energy's Office of Science.

If confirmed, ED138 would be among the largest dwarf planets discovered in this region of the solar system. Scientists plan to conduct further observations to determine its exact size and whether it qualifies as a dwarf planet.

This discovery adds to a growing list of recent findings that are helping to unravel the mysteries of the outer solar system. Pluto, once considered the ninth planet, was reclassified as a dwarf planet in 2006.