Astronomers identify possible dwarf planet beyond Pluto

Astronomers have identified a distant object that may be a dwarf planet, using observations from the Vera C. Rubin Observatory and older telescope images. Provisionally designated 2026 ED138, the object is about 46 astronomical units from the Sun, but researchers have not established whether it meets the criteria for dwarf-planet status. Matthew Holman, an astronomer at the Center for Astrophysics, found the candidate while analyzing Rubin data with search software developed with colleague Kevin Napier. The program looked for detections on different nights that could be linked by the motion of an object. Holman said his first reaction was excited disbelief, prompting him to check whether he or the software had made an error. Rubin recorded ED138 30 times across 20 nights between March 4 and July 11, 2026. Researchers also found the object in archival images from the Dark Energy Camera dating to 2016. Those earlier observations show that ED138 had been photographed years before its movement was recognized as evidence of a distinct object. The candidate lies in a crowded region near the apparent plane of the Milky Way, where numerous background stars can make faint, slowly...