Astronomers discovered a mysterious object named 2026 ED138 beyond Neptune on October 13. Matthew Holman found the icy body, which is 600-1,500km wide, using data from the Vera Rubin Observatory. "Objects like this are very rare," Holman said. This discovery could mean a new dwarf planet exists in our solar system.

Astronomers have discovered a mysterious object, dubbed 2026 ED138, in the frigid region beyond Neptune. The find was made by Matthew Holman from the Center for Astrophysics | Harvard & Smithsonian (CfA) while sifting through data from the powerful Vera Rubin Observatory in Chile. The icy body is estimated to be between 600-1,500km wide and possibly large enough to be a dwarf planet.

Holman made the discovery on October 13, while running Rubin data through a search code he developed with his CfA colleague Kevin Napier.

The search revealed 2026 ED138 as a bright object beyond Neptune's orbit, hinting at its size.

My first reaction was one of excited disbelief, Holman said after the discovery was announced on October 27. Objects like this are very rare.

The Vera Rubin Observatory, located on an 8,799-foot-tall mountain in northern Chile, has a massive catalog of data.

The observatory started its main project, the 10-year-long Legacy Survey of Space and Time (LSST), in June this year.

During the LSST, Rubin takes images of the entire southern sky every few days with a 3.2-gigapixel camera, the largest digital camera ever built for astronomy.

This survey is expected to reveal many more objects like 2026 ED138 in the future.

Holman and his colleague Mario Juric, who works at University of Washington and serves as Rubin Solar System Lead Scientist, discovered that Rubin observed 2026 ED138 over 20 nights between March 4 and July 11 this year.

The Dark Energy Camera (DEC) on Victor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile also detected the object.

The data shows an orbital tilt of about 25 degrees for 2026 ED138, possibly due to a gravitational interaction with Neptune.

The 2026 ED138 currently lies about 46 astronomical units from the Sun, beyond Pluto's average distance of 40 AU.

Its classification as a dwarf planet will depend on further observations in infrared light, a range best suited for NASA's James Webb Space Telescope.

If confirmed as a dwarf planet, ED138 would join a very small family of worlds, Holman said.