Astronomers have identified a potential new dwarf planet, temporarily named 2026 ED138, using the Vera C. Rubin Observatory in Chile.
The discovery was made using data from the Rubin Observatory, which is equipped with the world’s largest digital camera. The object was identified, and its discovery was officially announced at a scientific conference in Spokane, Washington.
Holman’s analysis detected the object. His initial reaction was one of excitement and disbelief.
Using other sources, researchers were able to map the object’s orbit as far back as ten years.
A Potential Sixth Dwarf Planet
If confirmed, 2026 ED138 would become the sixth recognized dwarf planet in our solar system, joining the existing five: Ceres, Pluto, Haumea, Makemake, and Eris.
The object is currently located about 46 astronomical units (AU) from the Sun. This is nearly 46 times the average Earth-Sun distance, placing it farther out than Pluto. It is classified as a trans-Neptunian object (TNO), residing in the Kuiper Belt, a region of the solar system beyond Neptune populated by countless icy bodies.
Meet our Solar System's newest dwarf planet candidate: 2026 ED138! Orbiting past Pluto, scientists found it in NSF–DOE Rubin Observatory data from earlier in 2026. Early analysis suggests it's 600–1500 km across, one of the largest found past Neptune! 🔗 https://t.co/wTOg898zBu pic.twitter.com/hEgnk597rl
The discovery changes how we understand the solar system’s outer regions.
Challenges in Confirmation
Despite the promising initial data, 2026 ED138 has not yet been officially classified as a dwarf planet.
For an object to be granted this status by the International Astronomical Union (IAU), it must meet three criteria: orbit the Sun, be massive enough to be nearly round under its own gravity, and have cleared the neighborhood around its orbit.
The primary challenge now is to determine the object’s exact size and shape.
NSF and DOE’s Rubin Observatory finds a dwarf planet candidate Beyond the orbit of Pluto, the NSF -DOE Vera C. Rubin Observatory has identified 2026 ED138, a newly discovered object and dwarf planet candidate. pic.twitter.com/9pGcdBvrIC
Holman stated that the team’s first task is to determine 2026 ED138’s true shape. The amount of light it reflects could correspond to a small but very bright object or a larger but dimmer one.
To resolve this, scientists plan to use powerful radio telescopes like the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. By observing the object’s own emitted light at long wavelengths, they can more accurately measure its size and composition.
Holman explained that this method will help determine the true dimensions of 2026 ED138.
Why It Remained Hidden
The reason 2026 ED138 remained undiscovered for so long is due to two main factors.
First, it is located in the southern celestial hemisphere, making it difficult to observe from the Northern Hemisphere.
Second, it lies in a region of the Milky Way galaxy where countless stars make it difficult to find moving objects. Identifying such objects in this environment requires specialized observation and advanced technology, which the Rubin Observatory is designed to provide.
The Rubin Observatory’s capabilities are expected to lead to many more discoveries in the coming decade. Scientists anticipate finding approximately 32,000 cosmic objects beyond Neptune’s orbit over the next ten years. Several are expected to be new dwarf planets.
