Astronomers find icy object beyond Neptune that may be a dwarf planet, 2026 ED138

Astronomers have found a surprising object at the extremely cold and dark edge of the solar system. It has been provisionally named '2026 ED138'. Scientists say it could be a dwarf planet. The discovery was made with the help of data gathered by the Vera C. Rubin Observatory in Chile.

If it is confirmed as a dwarf planet, it will be a very significant event in the history of astronomy. So far, only five dwarf planets have been officially confirmed in the solar system: Pluto, Ceres, Eris, Haumea and Makemake.

The object is possibly large enough to have become nearly round under its own heavy gravity. This is the feature that separates a dwarf planet from an ordinary asteroid or space rock. The icy body lies beyond Neptune's orbit, and its diameter is estimated at 600 to 1,500 km (about 373 to 972 miles).

It was discovered by Matthew Holman, an astronomer at the Center for Astrophysics (CfA | Harvard & Smithsonian). On October 13, 2026, Holman found the object in the Rubin Observatory's database using an advanced search code he built with his colleague Kevin Napier. Announcing the discovery, Holman said, "My first reaction was, is this really right? Because such large objects at this distance are very rare. To check whether there was some error in my code, I immediately began checking again in the Rubin Observatory's catalogue."

Further checks showed that the Rubin telescope had recorded the object several times between March and July in early 2026. Traces of the object were also found in a computer analysis of older telescope data from 2016. Despite being very far from the Sun, it appeared much brighter than expected. Scientists therefore concluded that it must be considerably larger than the other common trans-Neptunian objects (TNOs) found beyond Neptune.

The credit for the discovery goes to the Vera C. Rubin Observatory, built on Cerro Pachon mountain in northern Chile, at a height of 8,799 feet (2,682 metres). The observatory has a main mirror 28 feet (8.4 metres) wide. The telescope took its first images (First Light) in April 2025, and from June 2026 it has officially begun the 10-year Legacy Survey of Space and Time (LSST) project.

The project uses a 3.2-gigapixel camera, the largest digital camera ever built by humans. Every few days, the camera makes a high-resolution map of the entire southern sky. This has made it easier to find changes happening in the universe from moment to moment, new asteroids and distant dwarf planets.

'2026 ED138' is currently 46 astronomical units (AU) from the Sun. One AU is the average distance between the Earth and the Sun (about 150 million km). By comparison, the well-known dwarf planet Pluto is on average 40 AU from the Sun, which means the new object orbits the Sun at a greater distance than Pluto. Its orbit is tilted by 25 degrees to the plane of the solar system, which suggests that Neptune's gravity may have had an influence on it.

The International Astronomical Union (IAU) will not officially regard it as a 'dwarf planet' until astronomers determine its exact size and mass. For this, closer observations in infrared light will be made in the future with the help of NASA's James Webb Space Telescope (JWST).