While watching a tiny planet eclipse a very distant star, astronomers made an unexpected discovery: The egg-shaped world hosts a 43-mile-wide ring of particles and debris.

That egg, called Haumea, is now the first official dwarf planet found to host a ring system, and only the third body smaller than Neptune known to have rings. The discovery also marks the first time anyone has found rings around an object in the Kuiper belt, a region of icy bodies out beyond the orbit of Neptune.

Ultimately, the revelation may help scientists better understand why and how rings form. But it also gives planners for deep-space missions, like the New Horizons spacecraft that flew past Pluto, an extra item on the