Astronomers may have just discovered our solar system’s sixth dwarf planet (scientificamerican.com)
On Tuesday astronomers at the Vera C. Rubin Observatory announced the discovery of a new dwarf planet candidate in a distant part of the solar system beyond Neptune’s orbit. The new object doesn’t have an official name yet and is instead going by its provisional designation—2026 ED138.
The discovery was made by running billions of pieces of data collected by the Rubin Observatory through a search code developed by Center for Astrophysics | Harvard & Smithsonian astronomers Matthew Holman and Kevin Napier.
“My first reaction was one of excited disbelief,” Holman said in a statement. “Objects like this are very rare, so I immediately started checking whether I or the code had done something wrong.”
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The suspected dwarf planet is about 46 times as far from the sun as Earth, making it even more remote than Pluto, which is just 40 times as far. The object is also tilted off the solar system’s plane by around 25 degrees, an arrangement that could be linked to disruptions caused by Neptune’s gravitational pull.
Initial measurements indicate that 2026 ED138 has a diameter between 600 and 1,500 kilometers (373 and 932 miles), which makes it one of the largest dwarf planet candidates yet detected. But size isn’t all that matters: further observations are required to determine if the object has enough mass to be pulled into a round shape, which is a key requirement for a dwarf planet.