Dwarf planet candidate appears which takes roughly 280 years to orbit our sun

Astronomers identified 2026 ED138, a distant solar-system object that may be a new dwarf planet. Smithsonian Astrophysical Observatory astrophysicist Matthew Holman and colleagues first noticed it in images from Chile’s Vera C. Rubin Observatory, then confirmed it by finding the object in older observations, including photographic plates dating to 1937. It lies about 46 times farther from the Sun than Earth does and takes 281 years to complete an orbit. Its path is tilted nearly 25 degrees relative to the plane of the major planets, possibly because of gravitational interactions with Neptune. The object is one of thousands of small bodies found in Rubin data, but its apparent brightness suggested it could be unusually large.

To qualify as a dwarf planet, ED138 must be massive enough for its gravity to make it nearly round, while still sharing its orbital region with other debris. Current estimates put its diameter between roughly 370 and 930 miles, too broad a range to confirm its status: a small, bright icy body could look as luminous as a larger, darker one. Astronomers can narrow the estimate by measuring its infrared heat or timing how long it blocks a distant star. Its discovery could add to the five currently recognized dwarf planets and illuminate the solar system’s formation. It also demonstrates how much remains unknown in hard-to-survey regions of the sky, particularly the southern hemisphere and areas crowded by the Milky Way’s background light.