Astronomers using the Vera C. Rubin Observatory in Chile have identified a large icy body orbiting in the Kuiper belt beyond Pluto, designated temporarily as 2026 ED138, hvg.hu reported. The object has a estimated diameter ranging between 600 and 1,500 kilometers and travels at a distance roughly 46 times farther from the Sun than Earth, placing it among the largest trans-Neptunian objects discovered in the solar system’s outer reaches. Based on its size, it could be one of the largest known celestial bodies in the Kuiper belt.
Discovery at the Vera C. Rubin Observatory
The Vera C. Rubin Observatory detected the candidate dwarf planet during its early observation phases, operating atop the Cerro Pachón mountain. Matthew Holman, an astrophysicist at the Harvard & Smithsonian Center for Astrophysics, first spotted the object on October 13, 2026, while analyzing software data that compares moving celestial observations, according to Origo. Mario Jurić, a University of Washington astronomer and leader of the Rubin Observatory solar system research group, told Gizmodo that finding such a massive object occurs perhaps once in a generation.
Archival analysis revealed that the Dark Energy Camera photographed the object as early as February 2016, with subsequent detections in 2017, 2018, 2019, and 2023 without prior identification. Between March and July 2026, the Rubin system recorded the body across twenty different nights, generating thirty separate observations that allowed researchers to map its orbit.
International Astronomical Union May Officially Recognize 2026 ED138
If subsequent observations confirm its physical properties, the International Astronomical Union may officially recognize 2026 ED138 as the sixth dwarf planet, joining Pluto, Eris, Haumea, Makemake, and Ceres. The International Astronomical Union defines a dwarf planet as a celestial body in direct orbit around the Sun with sufficient mass for self-gravity to pull it into a nearly round shape, while failing to clear its orbital neighborhood of debris.
Phil Marshall, deputy director for Rubin Observatory operations, stated that the outer solar system ranks among the hardest regions to study due to the faint reflected light of small bodies. While Pluto orbits at roughly 40 astronomical units from the Sun, 2026 ED138 spans a distance fluctuating between 36.86 and 49.04 astronomical units over a 281-year orbital period. Holman noted that determining the exact size requires combining data from optical telescopes like Rubin, which measure reflected sunlight, with facilities like the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to detect thermal emissions.
Frequently Asked Questions About the Trans-Neptunian Discovery
What makes 2026 ED138 difficult to observe?
Observing trans-Neptunian objects is hindered because they receive very little light at great distances from the Sun. 2026 ED138 remained hidden because its orbit forms an angle of roughly 24.5 degrees with the plane of the solar system, and it was positioned in front of the dense star field of the Milky Way, where numerous background stars made it exceptionally difficult to spot.
How far is 2026 ED138 from the Sun?
The candidate dwarf planet orbits at an average distance of approximately 46 astronomical units, with its orbital path ranging from 36.86 to 49.04 astronomical units over a 281-year period.
Which telescopes recorded the object prior to its formal announcement?
The Vera C. Rubin Observatory captured twenty observations across twenty nights between March and July 2026, while archival searches showed the Dark Energy Camera photographed it as early as February 2016.
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