Astrology

Astronomers identify a possible dwarf planet beyond Neptune.

Astronomers have identified a possible dwarf planet beyond Neptune using the Vera C. Rubin Observatory, EarthSky reports. The object, designated 2026 ED138, could become the sixth officially recognized dwarf planet if its classification is confirmed.

EarthSky says astronomers announced the candidate on October 27, 2026. Its estimated diameter ranges from 600 to 1,500 kilometers, or 370 to 930 miles, based on its distance, brightness and reflectivity. Pluto, by comparison, measures 2,370 kilometers across.

Published

ED138 remains a dwarf planet candidate#

The candidate is about 46 astronomical units from the sun, according to EarthSky. An astronomical unit is the distance between Earth and the sun. Pluto's average distance from the sun is 40 astronomical units, although ScienceAlert says ED138's entire orbit falls within Pluto's range of distances.

A dwarf planet must have enough mass for its own gravity to make it round, SSBCrack reports. EarthSky says astronomers think ED138 is large enough to meet that condition, but its status remains unconfirmed. The five recognized dwarf planets are Pluto, Eris, Makemake, Haumea and Ceres.

Mario Juric of the University of Washington said the find was the largest trans-Neptunian object, meaning an object beyond Neptune, discovered in about 20 years. EarthSky reports that Rubin detected it while the telescope was still being commissioned.

Rubin's survey data revealed the object#

Matthew Holman of the Center for Astrophysics led the analysis of data gathered earlier in the year, Udaipur Kiran reports. SSBCrack says Holman used search code to identify moving objects among billions of detections and match the same object across observations.

The observatory is in Chile and is preparing a 10-year survey of the southern sky, according to Udaipur Kiran and Wikipedia. ScienceAlert reports that Rubin's 3.2-gigapixel camera can capture an area equivalent to about 40 full moons in one exposure.

Holman said determining the object's physical size would probably take a few months, according to Udaipur Kiran. The outlet reports that confirmation would involve further infrared observations, likely using the James Webb Space Telescope.

Discover more