11-Feb-2023: Unusual rings detected around the dwarf planet Quaoar

Quaoar, a dwarf planet beyond Neptune was identified with unusual rings.

• Rings are positioned at a distance of over seven planetary radii.
• Rings are much further away from other planets with rings.

Study shows the ring system is challenging previous notions of how such rings form. Planetary rings contain small chunks of ice and other materials that orbit a larger object. Only Saturn, Jupiter, Uranus, Neptune, including two other minor planets, Chariklo, and Haumea are known to have rings.

The rings of Quaoar were discovered while studying distant objects in our solar system. Researchers used an extremely sensitive high-speed camera mounted on the Gran Telescopio Canarias in Spain. Occultations were used to study the objects. Dip in brightness was identified, as Quaoar blocked light from a background star, which led to the discovery of the ring system.

The rings’ position contradicts the Roche limit. Roche limit is the outer limit of where ring systems were thought to be able to survive. Tidal forces prevent the rings from aggregating to become natural satellites. Rings of other planets lie within the Roche limit.

The question of why the rings of Quaoar have not coalesced into a satellite is not clear. The new finding will provide further insight into how planetary rings form.