Chen, Ying-Tung, Lin, Hsing Wen, Holman, Matthew J., Payne, Matthew J., Fraser, Wesley C., Lacerda, Pedro, Ip, Wing-Huen, Chen, Wen-Ping, Kudritzki, Rolf-Peter, Jedicke, Robert, Wainscoat, Richard J., Tonry, John L., Magnier, Eugene A., Waters, Christopher, Kaiser, Nick, Wang, Shiang-Yu, and Lehner, Matthew J. 2016. "Discovery of a New Retrograde Trans-Neptunian Object: Hint of a Common Orbital Plane for Low Semimajor Axis, High-inclination TNOs and Centaurs." Astrophysical Journal Letters 827:L24. https://doi.org/10.3847/2041-8205/827/2/L24
Although the majority of Centaurs are thought to have originated in the scattered disk, with the high-inclination members coming from the Oort cloud, the origin of the high-inclination component of trans-Neptunian objects (TNOs) remains uncertain. We report the discovery of a retrograde TNO, which we nickname “Niku,” detected by the Pan-STARRS 1 Outer Solar System Survey. Our numerical integrations show that the orbital dynamics of Niku are very similar to that of 2008 KV42 (Drac), with a half-life of ˜500 Myr. Comparing similar high-inclination TNOs and Centaurs (q > 10 au, a 60°), we find that these objects exhibit a surprising clustering of ascending node, and occupy a common orbital plane. This orbital configuration has high statistical significance: 3.8-σ. An unknown mechanism is required to explain the observed clustering. This discovery may provide a pathway to investigating a possible reservoir of high-inclination objects.