New Ring System Discovered in Our Solar System
A team of international scientists discovered a new ring system relatively nearby. Quaoar, a dwarf planet, orbits beyond Neptune and is challenging current ring formation theories.
The team used HiPERCAM, an extremely sensitive high-speed camera mounted on the Gran Telescopio Canarias (GTC)—the world’s largest optical telescope on La Palma in the Canary Islands.
Quaoar, about half the size of Pluto, sits on the very edge of the Solar System. Its rings orbit much further than is typical, leaving astronomers scrambling to adapt current theories on ring system formation.
Quaoar’s rings are too small and faint to see directly in an image; the researchers discovered them by observing an occultation. This occurs when a planet blocks light from a background star as it orbits. The occultation event lasted less than a minute but was preceded and followed by two dips in light, indicating the presence of a ring system.
Ring systems are rare in our Solar System. The most famous surround Saturn, Jupiter, Uranus, and Neptune. Two other ring systems orbit Chariklo (the first asteroid with a ring system) and Haumea (a dwarf planet beyond Neptune in the Kuiper Belt).
Ring systems were thought to survive due to their proximity to their parent body. The tidal forces in the system prevent them from accreting and forming into moons. However, the rings around Quaoar lie over seven planetary radii beyond the dwarf planet—twice as far as the maximum distance, or “Roche Limit,” astronomers believed necessary for ring systems to survive. The main rings around Saturn are within three planetary radii.
The study involved 59 academics from all over the world. They published their findings in Nature.
