2026 ED138, spotted in Vera C. Rubin Observatory data, appears to be 370 to 930 miles wide and could rank among the largest dwarf planets found in the outer solar system.
Rubin's newly launched 10-year sky survey and software built by Matthew Holman and Kevin Napier pulled the object from a crowded Milky Way star field that had masked it from earlier telescopes.
The trans-Neptunian object lies about 4.3 billion miles from the sun, beyond Pluto's average 3.7 billion-mile orbit, making follow-up observations crucial to pin down its size and status.
If confirmed, ED138 would join a small group of recognized dwarf planets and underscore Rubin's potential to uncover more large bodies missed in previously hard-to-search regions.