Rubin Observatory Spots a New Dwarf Planet Candidate Hiding in the Milky Way

The NSF–DOE Vera C. Rubin Observatory has found a large object that scientists say could be a dwarf planet. Early data place it in the outer solar system, beyond Pluto, and suggest it may be one of the biggest dwarf planet candidates ever identified.

The object, provisionally named ED138, was found close to the plane of the Milky Way, an area so filled with stars that it likely obscured the object until now. Rubin's regular monitoring and data algorithms were able to pick out ED138's motion against that crowded backdrop.

If follow-up observations confirm the finding, ED138 would join Pluto, Ceres, Eris, Haumea, and Makemake as the sixth recognized dwarf planet.

Rubin Observatory is jointly funded by the U.S. National Science Foundation and the U.S. Department of Energy's Office of Science. It uses the largest digital camera ever built for astronomy, allowing it to rapidly and repeatedly image the southern sky and detect subtle changes.

The International Astronomical Union's Minor Planet Center has assigned the provisional designation ED138. Other observatories can now conduct follow-up observations to learn more about its size, mass, and orbit.

The population of large bodies in the outer solar system is a direct clue to how planets formed and how the Kuiper Belt evolved. If a sizable dwarf planet candidate has been hiding in plain sight, current surveys may still have blind spots.

Rubin is only beginning its full survey, yet it already submitted more than 11,000 new asteroid observations in April 2026. Its ability to spot moving objects in crowded fields will likely reshape the solar system map over the next few years.

The discovery demonstrates a key capability of Rubin: finding moving objects against extremely dense star fields. That same capability may uncover many more distant solar system bodies that have been missed.

ED138 was discovered by the Rubin Observatory, funded by NSF and DOE.

Preliminary analysis places it in the outer solar system, beyond Pluto's orbit.

Its provisional designation is ED138, and it is currently a dwarf planet candidate.

The object lies near the Milky Way's plane, where dense starlight makes detection difficult.

The public can explore ED138's orbit using Orbitviewer, an interactive web app.

The object's exact size, mass, and orbital parameters have not been finalized.

It has not yet been formally confirmed as a dwarf planet by the International Astronomical Union.

All current information comes from the NSF release; independent observations and peer review are still pending.

The claim that it is among the largest dwarf planet candidates ever found needs more precise follow-up measurements.

April 2026: Rubin Observatory submits observations of more than 11,000 new asteroids.

October 27, 2026: NSF publishes a news release announcing the discovery of dwarf planet candidate ED138.