Astronomers sorting through data from the Vera C. Rubin Observatory in Chile have found an icy world that has a good chance of joining Pluto in the solar system’s retinue of dwarf planets.
University of Washington astronomer Mario Jurić joined the astronomer who made the discovery, Matthew Holman of the Harvard & Smithsonian Center for Astrophysics, to announce the findings today at a meeting of the American Astronomical Society’s Division for Planetary Sciences in Spokane, Wash.
Jurić, the Rubin team’s solar system lead scientist, said the observatory’s capabilities made it possible to detect and characterize the new dwarf planet candidate, known as 2026 ED138.
“Rubin is giving us an unprecedented capacity to explore the sky through a combination of speed, depth, and precision,” Jurić said in a news release. “And the discovery is just the beginning: Once we identify a new object, we can search back months, and sometimes even decades, finding it in images where nobody knew to look. This ability to both discover and ‘precover’ objects is transforming how quickly and accurately we can determine their orbits and understand the distant solar system.”
2026 ED138 traces a tilted orbital path that takes it well beyond Pluto, the solar system’s best-known dwarf planet. It’s currently at a distance of 46 astronomical units, where 1 AU equals the average distance between Earth and the sun. Pluto, by comparison, is currently about 40 AU from the sun. Astronomers suspect ED138 formed billions of years ago closer to the sun before being flung into a wider orbit by gravitational interactions with Neptune.
