Another ‘Impossible’ Ring Discovered Encircling a Faraway Dwarf Planet

Astronomers revealed earlier this year that a small planet beyond Neptune, with a diameter roughly one-third that of Earth’s moon, has a Saturn-like ring when there shouldn’t be one. Two “impossible” rings have been discovered.

The new ring is around 1,500 miles in circumference and is about six miles broad, encircling the planet Quaoar. This Friday, the research will be made public in the online edition of Astronomy & Astrophysics Letters.

Dust and gas in the early solar system formed into planets and moons in mysterious ways that scientists still do not completely comprehend.

The second ring orbiting Quaoar, like the first ring revealed in February by a team of astronomers, extends beyond the Roche limit. Any material in orbit that is closer than this distance experiences significant tearing due to tidal forces. If a ring is found within the Roche limit, it will likely continue to exist as a ring, whereas if it is found outside, it will likely combine into a moon.

It has been determined that the Roche limit for Quaoar is 1,100 miles. The new ring is far closer to the centre of Quaoar than the ring disclosed in February, which had a radius of around 2,500 miles. It is located 1,500 miles away.

The Indigenous Tongva people of the Los Angeles area worship the sun deity Quaoar (KWA-wahr), which is located in the Kuiper belt of icy debris beyond Neptune.

Telescope photos do not reveal the ring. Instead, it was discovered indirectly when a passage of faraway stars blocked the light from Quaoar and revealed the planet to the researchers. From 2018 through 2021, Quaoar occulted, or passed in front of, four stars, allowing Earth-based astronomers to see eclipses of the stars.

Before and after the star blinked out, they saw a decrease in brightness, suggesting the presence of the first ring.

In the hopes of learning more about the ring, scientists once again focused big and tiny telescopes towards Quaoar on August 9 of last year, when another occultation occurred.

The new discoveries shed light on previously hidden features of the ring, such as its compact, narrow core that is just a few miles broad, and its more diffuse outer envelope. The second ring was also seen thanks to the observations.

On May 13, another occultation will be seen via telescopes in North America.

The existence of Quaoar’s moon, Weywot, may provide an explanation for its distant rings. Gravitational disruptions caused by the moon may have stopped the ring’s particles from accreting into other moons. Both rings are located close to what are called resonances with Weywot; these resonances may prove to be more significant than the Roche limit in deciding whether rings evolve into moons or stay as rings.