Astronomers have discovered an entirely new ring system within our solar system. That shouldn’t be possible because it’s so far away from its dwarf planet parent.
The rings surround Kuaoa, which is about half the size of Pluto and lies outside Neptune. This is her third ring found around an asteroid, along with the most famous and well-studied rings surrounding the giant planets Saturn, Jupiter, Neptune and Uranus, and her seventh ring system in the solar system. is.
“six [previously known] All planets with ring systems have rings that are very close to the surface of the planet. physics and astronomy professor Vic Dillon told Live Science. In a nutshell, Kuaor’s Ring is very difficult to explain theoretically. “
Related: Neptune’s ghostly rings glow in new James Webb telescope image
The ring system is located at a distance of 7 planet radii from Quoa (that is, 7 times the radius of Quoa). This is twice the theoretical maximum limit for ring systems known as the Roche limit. For comparison, the main part of Saturn’s rings lies just three planetary radii from the gas giant.
It was previously thought that rings beyond Roche’s limits would not survive away from their parent body.
“A ring formed outside the Roche limit is not stable. “This discovery yields a ring that is not just outside Roche’s limits, but well beyond them.”
The team’s findings were published in Nature on February 8.
How dwarf planets grew distant rings
Dhillon and team believe that Quaoar’s rings formed like other solar system rings: Collisions of small satellites orbiting the parent planet settled debris in rings of rock, ice and dust particles. was created.
These particles cannot reform into small satellites if they are close to the planet and within the Roche limit, researchers say. This is because the tidal forces from the mother body constantly tear them apart, preventing them from clumping together.
“We have to find some way to stop the formation of moons at that distance,” Dillon said. “The particles in the ring are colliding all the time, and if these collisions are elastic, it means that the particles cannot stick together to form satellites.” , collisions that bounce off each other rather than sticking together, like rubber balls hitting the floor.)
If the ring particles are covered with ice on the outside, elastic collisions can occur, Dhillon said. This is plausible given that Kua Oa is located on the edge of the solar system. However, more data are needed to confirm this idea.
accidental discovery
Researchers discovered the ring system while investigating whether Kua Oa had an atmosphere. Using high-speed HiPERCAM instruments at the Gran Telescopio Canarias, a telescope in the Canary Islands of Spain, the team was able to spot subtle variations in light from background stars. The rings became visible when the light from the background star dropped by about 5% to 10% before and after the Quaor body passed in front of the star. This event, known as an occultation, lasted less than a minute.
“This discovery came as a bit of a surprise,” Dhillon said. “I knew I could find it, but I wasn’t actually looking for it.”
Quaor’s rings are too small and faint to be seen in direct images, even with powerful instruments such as the Hubble Space Telescope. Dillon added that the only way to find these dwarf planet rings, other than an occultation event, is to send a robotic probe to visit them.
“This discovery shows the amazing diversity of what lies in our own cosmic backyard,” Dillon said. No need to look, our own solar system still holds many surprises.”
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