The first trans-Neptunian object discovered after Pluto. It was the first classical Kuiper Belt object discovered and other objects in this portion of the belt (just beyond Neptune, low eccentricity, not in resonance with Neptune) are called "Cubewano"s in its honor. Also has a low inclination, making it a dynamically cold classical KBO. Its discoverer suggested the name Smiley, but this was already used for an asteroid. About 160 km across.