Amateur Astronomers Association of Princeton (AAAP) Monthly Meeting

Astronomers Jiaxuan Li and Eritas Yang (graduate students at Princeton University’s Department of Astrophysics) and Sihao Chang (Institute for Advanced Study) identified a remarkable new world in the far outer Solar System: a dwarf-planet candidate named 2017 OF201, currently more than 90 times farther from the Sun than Earth. By combining observations spanning the past two decades, the team showed that it follows an enormous, elongated orbit that reaches deep into the inner Oort Cloud. With an estimated diameter of roughly 700 km, it ranks among the largest known objects on such distant orbits and is very likely a dwarf planet. Its extreme trajectory hints at a far larger, still-hidden population of similar bodies that may collectively contain about 1% of Earth’s mass. Intriguingly, its orbit does not share the clustering seen in some other remote objects — a pattern often cited as evidence for a possible “Planet Nine.” Continued searches for distant Solar System bodies will help unveil the true structure and diversity of this unexplored frontier.