Astronomers have identified a distant, icy object in the outer solar system that could qualify as a dwarf planet. Named 2017 OF201, the object spans about 435 miles (700 km) and travels along an extremely elongated orbit, taking approximately 25,000 years to circle the sun.
Currently about 90.5 astronomical units from the sun—over 90 times Earth’s distance—2017 OF201 can reach more than 1,600 astronomical units at its furthest point, placing it well beyond Pluto. Its closest approach, however, brings it within 45 AU, occasionally nearer to the sun than Pluto itself.
The discovery, made over seven years using telescopes in Chile and Hawaii, was announced by the Minor Planet Center of the International Astronomical Union and detailed in a study posted on arXiv.
“This object is potentially large enough to be a dwarf planet,” said lead researcher Sihao Cheng of the Institute for Advanced Study in Princeton. Its mass is estimated to be about 20,000 times smaller than Earth’s and 50 times smaller than Pluto’s.
The object’s unusual orbit and remote location challenge previous assumptions that space beyond Neptune and the Kuiper Belt is mostly empty. It may also raise questions about the hypothesized existence of a ninth planet, as 2017 OF201 does not follow the orbital clustering seen in other trans-Neptunian objects.
Scientists believe its orbit could have been influenced by a distant encounter with a massive planet. While its shape and composition remain unknown, it’s thought to be similar to other icy bodies in the region.
So far, only five dwarf planets are officially recognized: Ceres, Pluto, Haumea, Makemake, and Eris. 2017 OF201 could soon join their ranks—pending further observation and confirmation.
