Giant dwarf planet candidate discovered in Kuiper Belt

Summarised from 2 outlets · Updated 29 Oct, 09:20 · Archive

Astronomers have discovered a large object beyond Pluto that may be a new dwarf planet.

Astronomers have discovered a large object in the Kuiper Belt that may be a new dwarf planet. Named 2026 ED138, it measures between 600 and 1,500 kilometres in diameter and orbits about 46 astronomical units from the sun. For comparison, Pluto orbits at an average distance of 40 astronomical units from the sun.

The object was spotted by Matthew Holman, a researcher at Harvard-Smithsonian Center for Astrophysics, on 13 October 2026 while analysing data from the Vera C. Rubin Observatory in Chile. The observatory features the largest digital camera ever built for astronomy. The team traced 2026 ED138 through 30 detections across 20 nights of observations from 4 March to 11 July 2026.

Searching older data, the team found the object in images from the Dark Energy Camera dating back to February 2016, and in subsequent images from 2017, 2018, 2019 and 2023. The object had remained hidden because its position in the night sky lies against the disk of the Milky Way. Astronomers are still working to confirm whether it meets the full criteria for a dwarf planet, which must orbit the sun and have sufficient gravity to assume a nearly spherical shape, though it may coexist with other objects in its region rather than clearing its orbit.

How it is being reported

• Astronomers Discover a Possible New Dwarf Planet in Our Solar SystemLying beyond Pluto, 2026 ED138 could be as large as 1,500 kilometers in diameter. Astronomers are still working to confirm whether it meets the criteria for a dwarf planet.Wired · 29 Oct, 09:00
• Giant new dwarf planet discovered in our own solar system — hiding in plain sightA large object in the Kuiper Belt — a distant region of icy and rocky bodies past Neptune — appears to be a new candidate dwarf planet.New York Post · 28 Oct, 17:23

In this story: 2026 ED138 · Vera C. Rubin Observatory · Matthew Holman · Harvard-Smithsonian Center for Astrophysics · Kuiper Belt · Pluto · Neptune

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