A new icy object has just been spotted very far from the Sun. It could be a dwarf planet, like Pluto.
Its provisional name is 2026 ED138. The Vera C. Rubin Telescope, located in Chile, observed it several times in spring 2026. On October 13, astronomer Matthew Holman noticed its movement in the images. After checking the data, he realized that it was an especially large and distant body.
Representation of the orbit of 2026 ED138 in turquoise, compared with those of the giant planets in the Solar System.
Credit: NSF–DOE Rubin Observatory/NOIRLab/SLAC/AURA/R. Proctor, M. Zamani, MPC, NASA and ESA/Gaia.
Currently, 2026 ED138 is about 46 times the distance between Earth and the Sun away. It belongs to the population of trans-Neptunian objects, which travel beyond Neptune's orbit. This region contains many icy bodies inherited from the formation of the Solar System.
The object is bright enough for astronomers to suspect that it is large. They estimate its diameter to be between 600 and 1,500 km. Why such a difference? Because a bright object reflects more light than a dark object of the same size, and researchers do not yet know the exact nature of its surface.
At this size, its gravity could be enough to give it an almost round shape. This is an expected property of dwarf planets. But scientists still need to confirm its dimensions. For now, 2026 ED138 therefore remains a candidate, not a new officially recognized dwarf planet.
Apparent movement of 2026 ED138 among the stars in May 2026. The turquoise circles indicate its successive positions in the Rubin Observatory images.
Credit: NSF–DOE Rubin Observatory/NOIRLab/SLAC/AURA, M. Jurić, D. de Martin and M. Zamani. CC BY 4.0.
The team also discovered that this celestial body had been hiding in astronomical archives for a long time. After identifying it, the researchers found observations dating back to 2016. They now have more than ten years of data to calculate its orbit.
Yet no one had noticed it until now. In the sky, 2026 ED138 appears in front of a very dense region of stars in our Milky Way. Its slow movement is difficult to distinguish among all these points of light. The Rubin Telescope's software can compare many images to find such objects.
Its orbit is tilted by about 24 degrees relative to Earth's orbit. Astronomers believe that gravitational interactions with Neptune could explain this orientation. It thus provides clues about the ancient movements of the giant planets.
New observations, particularly in infrared, should make it possible to estimate its size more precisely. The Rubin Telescope will simultaneously continue surveying the sky for several years, searching for other worlds still unknown.