New Telescope Finds Massive Object Beyond Pluto
Astronomers using the Vera C. Rubin Observatory identified a candidate dwarf planet measuring up to 930 miles across in a crowded section of the sky.
By Anthony Lawson ·
Astronomers identified a new celestial body beyond Pluto that may rank among the largest dwarf planets in the solar system. The object, designated 2026 ED138, was detected using data from the Vera C. Rubin Observatory in Chile. The facility began its ten year survey of the sky in June 2026.
The discovery was announced on Oct. 27. Researchers estimate the object measures between 370 and 930 miles across. It currently orbits the sun at a distance of 4.3 billion miles. This places it farther from the sun than Pluto, which averages 3.7 billion miles from the star.
Matthew Holman, an astronomer, found the object on Oct. 13. He used computer software he developed with colleague Kevin Napier to analyze telescope data from earlier this year. Holman noted that the object's brightness and distance indicated it was unusually large. He described his initial reaction as one of excited disbelief.
"Objects like this are very rare, so I immediately started checking whether I or the code had done something wrong," Holman said. The observatory stated that if confirmed, ED138 would be one of the largest dwarf planets ever found in that region of the solar system.
Scientists classify ED138 as a trans-Neptunian object because it orbits beyond Neptune. The body had remained hidden because it sits in a dense area of the sky near the Milky Way. Millions of stars in that region made it difficult for previous telescopes to detect. The Rubin Observatory's continuous monitoring and advanced algorithms allowed the team to isolate the moving object among the background stars.
The object is large enough to be nearly round but has not cleared its orbital region of other debris. Pluto holds a similar classification after being reclassified from a planet to a dwarf planet in 2006. Holman said that if ED138 is confirmed as a dwarf planet, it will join a small group of similar worlds.
Further observations are planned to determine the exact size of the object. The Rubin Observatory will continue imaging the southern sky over the next decade. This ongoing survey aims to find other objects that previous surveys missed.
