Astronomers analysing data from the Vera C. Rubin Observatory in Chile have discovered a potential new dwarf planet in the distant outer reaches of the solar system, temporarily designated as 2026 ED138.
Temporarily tracked as 2026 ED138, the frozen body is a candidate to join the elite roster of officially recognised dwarf planets orbiting the sun.
Researchers identified the object by processing observations through a specialised computer program designed to sift through billions of moving celestial entities. The discovery was announced at a meeting of the Division for Planetary Sciences of the American Astronomical Society, held in Spokane, Washington.
How 2026 ED138 Was Found in Rubin Observatory Data
The discovery emerged from the wide-eyed scanning capacity of the Vera C. Rubin Observatory, which houses the world's largest digital camera and sweeps the entire sky every three days.
A new Dwarf Planet? Meet 2026 ED138, recently discovered by the Vera C. Rubin Observatory @VRubinObs. This Trans-Neptunian Object (TNO) is estimated to be 600–1,500 km across. 🔭 #astro pic.twitter.com/wJpAp1DdAj
I was very excited. And I couldn’t believe it either. This kind of thing is extremely rare. That’s why I checked over and over again to see if there was a mistake somewhere.
Juric scoured the observatory's database and located 20 previous observations of 2026 ED138 dating back to March 2026. By pulling in data from other observational sources, researchers managed to reconstruct the object's orbital path tracing back nearly a decade.
The object had actually been captured on camera previously by the Dark Energy Camera in 2017, 2018, 2019, and 2023, but its true significance went unnoticed at the time. Its orbital path tilts at an angle of roughly 24.5 to 25 degrees relative to the main plane of the solar system, and it has spent years travelling through the dense star fields of the Milky Way, where its faint glow blended into the background.
Size, Orbit, and Physical Characteristics of the Candidate Dwarf Planet
Preliminary calculations place 2026 ED138 at a distance of about 46 astronomical units from the sun, putting it well beyond Pluto and deep inside the Kuiper Belt, a ring-shaped region packed with icy bodies. One astronomical unit represents the average distance between the Earth and the sun.
If the upper range of that estimate proves accurate, 2026 ED138 would eclipse Ceris, currently the smallest recognized dwarf planet in the solar system, and rank as the largest dwarf planet discovered yet in that distant sector. A single orbit around the sun takes the object approximately 281 years.
While the object’s brightness and distance point toward a substantial physical scale, exact measurement remains tricky. Icy, reflective surfaces can make small objects appear brighter than they actually are, leaving researchers dependent on further observation to pin down precise dimensions.
Implications for the International Astronomical Union Dwarf Planet Roster
The formal classification of 2026 ED138 rests with the International Astronomical Union, the governing body that famously reclassified Pluto in 2006 by establishing three strict criteria for planethood: an object must orbit the sun, possess sufficient mass to form a near-round shape under its own gravity, and clear its orbital neighborhood of competing bodies. Pluto fell short of the third rule because it shares its orbital zone with other large icy bodies.
Should subsequent tracking confirm its physical profile, 2026 ED138 will join an exclusive group of five officially designated dwarf planets: Ceres, Pluto, Haumea, Makemake, and Eris.
It’s big enough that you can think of it as a world in its own right.
Banister suggested that if a spacecraft were ever sent to 2026 ED138 in the future, investigators might find nitrogen glaciers comparable to those observed on Pluto. For now, researchers stress that the object remains a candidate requiring months of additional telescope time to secure official standing, permanent catalog numbering, and a proper name.
