Rubin Observatory Uncovers Massive Trans-Neptunian Object 2026 ED138
The Vera C. Rubin Observatory has identified a massive, icy body designated 2026 ED138, which may be the solar system’s sixth recognized dwarf planet. Discovered by Matthew Holman and Mario Jurić, the object orbits the Sun at approximately 46 astronomical units, farther than Pluto. Estimated to be between 600 and 1,500 kilometers wide, it is large enough to potentially be spherical, a key criterion for dwarf planet status. While its existence is confirmed by archival data dating back to 2016, its official classification awaits further infrared observations to verify its size and shape.
Key points
- 2026 ED138 was discovered by Matthew Holman using Rubin data, with confirmation from Mario Jurić.
- The object orbits at 46 astronomical units, beyond Pluto’s average distance of 40 AU.
- Its estimated diameter ranges from 600 to 1,500 kilometers, making it larger than Ceres.
- Archival observations from 2016 and 2026 confirm its orbit and trajectory.
- Official dwarf planet status requires further infrared measurements to confirm its spherical shape.
Background
The Vera C. Rubin Observatory began its decade-long Legacy Survey of Space and Time in late June 2026. It is equipped with the largest digital camera ever built for astronomy, capable of imaging the entire southern sky every three days. The observatory has already discovered over 11,000 new asteroids, and 2026 ED138 is among its most significant finds to date.
How outlets are covering it
Gizmodo emphasizes the rarity of such a large trans-Neptunian object, noting it is the largest found in about 20 years. CNN highlights the challenges in observing the object due to its location in the southern hemisphere and its proximity to the Milky Way’s plane, which obscured it from northern hemisphere telescopes. Space.com notes that the object’s orbit is tilted by about 25 degrees, suggesting a past gravitational interaction with Neptune. All sources agree that while the object’s existence is confirmed, its classification as a dwarf planet remains pending further observations.
Why it matters
The discovery of 2026 ED138 underscores the power of the Rubin Observatory to uncover hidden bodies in the outer solar system. If confirmed as a dwarf planet, it would join a small group of five recognized dwarf planets, providing new insights into the formation and evolution of the solar system. The object’s size and brightness make it a prime candidate for future study, potentially revealing features like nitrogen glaciers similar to those on Pluto.
What to watch
Astronomers plan to use infrared observations, possibly from the James Webb Space Telescope, to confirm the size and shape of 2026 ED138. If confirmed as a dwarf planet, it will be assigned a permanent number and name, a process that may take time. The Rubin Observatory is expected to continue discovering similar objects in the coming years as it completes its decade-long survey.
- Rubin Observatory Discovers Possible New Dwarf Planet Gizmodo
- ‘It’s big’: Astronomers make startling discovery of a possible dwarf planet beyond Pluto CNN
- Rubin Observatory reveals its first dwarf planet candidate in our solar system Phys.org
- Astronomers found a mysterious object beyond Neptune, and it could be a new dwarf planet Space
- Possible new dwarf planet identified orbiting beyond Pluto Reuters
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