Astronomers Identify Large Trans-Neptunian Object 2026 ED138 Beyond Pluto

Astronomers have identified a large trans-Neptunian object designated 2026 ED138 located beyond Pluto, though scientists have not yet confirmed whether it qualifies as a dwarf planet. The discovery introduces a potential new candidate that awaits further infrared observations and classification.

According to reports based on data from the NSF–DOE Vera C. Rubin Observatory and announced by the International Astronomical Union's Minor Planet Center, the object was identified by Matthew Holman of the Center for Astrophysics | Harvard & Smithsonian. Initial estimates indicate the object could measure between 600 and 1,500 kilometres across and is currently situated about 46 astronomical units from the Sun.

Discovery and Observations

• Identified using Rubin Observatory data by analysing moving objects among billions of detections.
• Archival data from the Dark Energy Camera and the Asteroid Institute's ADAM Precovery service extended the observation record back to 2016.
• The object was recorded 30 times on 20 nights between March 4 and July 11, 2026.

Classification Status and Requirements

To achieve official dwarf planet status, an object must orbit the Sun, possess sufficient gravity to attain a nearly round shape, and not have cleared its orbital neighborhood. While initial size and brightness estimates suggest ED138 is likely round, researchers state that follow-up infrared observations are necessary to establish its precise dimensions and confirm its nature.

• Confirmed Information: 2026 ED138 is a trans-Neptunian object orbiting beyond Neptune, currently classified as a candidate dwarf planet.
• Reported Claims: Estimated diameter ranges from 600 to 1,500 kilometres, with an orbit tilted nearly 25 degrees relative to the plane of the Solar System.
• Unknowns: Exact size, definitive shape confirmation, and final classification remain subject to future infrared data.

Practical Implications and Verification

The finding highlights the capabilities of modern sky surveys in identifying faint outer Solar System objects in crowded regions near the Milky Way plane. Researchers can verify the discovery details through official announcements by the International Astronomical Union's Minor Planet Center and upcoming scientific publications regarding follow-up infrared observations.