Rings are not exclusive to the Solar System’s gas giants. Two minor planets also sport them, and now astronomers know how they formed.

Minor planets include objects like dwarf planets, asteroids, and asteroid-like objects found between Jupiter and Neptune called centaurs. An international team of astrophysicists simulated how centaurs interact with the giant planets and, according to their study published in the Astrophysical Journal Letters, the large planet rips the surface of the minor planet, and the debris sets into a ring.

The researchers believe that at least 10 percent of the centaurs, objects between Jupiter and Neptune, will experience the close encounters that lead to this effect. With over 44,000 centaurs with a diameter larger than 1 kilometer (0.62 miles), it is important to understand more about these numerous objects.

The study was started by the recent discovery of two ringed centaurs, Chariklo and Chiron. The rings were discovered thanks to a technique called stellar occultation, observations made when the minor planets were passing in front of a star. When this happened in 2013, astronomers were ready to look at Chariklo and discovered that the centaur, which has a diameter of 250 kilometers (160 miles), had ice water rings.

Chiron, which is slightly smaller, had actually been observed with this technique several times before Chariklo, but the ring signature was only understood afterward. Both objects have rings made of water ice, which suggests an icy surface is a necessary condition for the formation of this type of rings.

According to the researchers, there are other factors at play. The spin of the centaurs, their core size, and how close they get to the planet all influence if and how these minor planets get rings. But although exciting, rings are not the only things that could be formed around these objects. The simulations suggest that even small moons could form out of these interactions.

The centaur population might have looked like an unremarkable collection of comets and asteroids, but the more observations we get the more it seems to be full of interesting and unique objects. And if this study is correct, the best is yet to be discovered.