Rubin Observatory team reports 2026 ED138, a possible large dwarf planet beyond Pluto

Mixed · 2Astronomers using the Vera C. Rubin Observatory in Chile have identified an object called 2026 ED138 beyond Pluto, which could be among the largest dwarf planets found in that region of the solar system if confirmed. 1 2 Right · 1Fox News reports the announcement was made on Oct. 27, and that Rubin astronomer Matthew Holman spotted the object on Oct. 13 while using software he developed with colleague Kevin Napier to search telescope data collected earlier this year. 1 Left · 1Metro gives a fuller observation history: a bright speck was seen on March 4, it had moved when looked at again weeks later, and its orbital arc was mapped from March to July. Metro adds that the object also appears in earlier images from other telescopes. 2

Mixed · 2Fox News gives a size estimate of 370 to 930 miles across, while Metro cites only Holman's estimate of up to 930 miles. Fox says the object is currently about 4.3 billion miles from the sun, against about 3.7 billion miles for Pluto's average distance. 1 2 Right · 1The observatory said the object's brightness and distance suggested it is unusually large. Holman described his reaction as "one of excited disbelief" and said he checked whether he or the code had made an error. 1 Right · 1Officials said it had gone unseen because it lies in a crowded region of sky near the Milky Way, and that Rubin's continuous monitoring of the southern sky and its algorithms allowed the team to find it. 1

Mixed · 2Further observations are needed to pin down its size and whether it qualifies as a dwarf planet, and Metro notes the International Astronomical Union has not yet confirmed it. If it is confirmed, it could be named, and Metro counts it as the sixth dwarf planet after Ceres, Pluto, Eris, Haumea and Makemake. 1 2 Left · 1Metro reports that the object's orbital tilt suggests it formed near Jupiter and Saturn and was flung outward by a gas giant. It also says ED138 is not the hypothesised Planet Nine, which some scientists propose to explain the clustering of six distant objects. 2 Left · 1Dr Edward Bloomer of the Royal Observatory Greenwich told Metro the find shows scientists have not stopped exploring. 2

Right · 1Fox News adds that Rubin is funded jointly by the US National Science Foundation and the Department of Energy's Office of Science and began a 10-year sky survey in June 2026. Holman said other such worlds may be hiding in places earlier surveys skipped. 1