New telescopic data has revealed a dense ring surrounds a dwarf planet in the outer reaches of the Solar System, leaving scientists and astronomers confused as to why.
Scientists from the European Space Agency announced on Wednesday that data and observations of the planet Quaoar collected between 2018 and 2021 by ground-based telescopes and the space-based telescope Cheops led them to the discovery.
ESA revealed Quaoar flew in front of a series of distant stars, blocking their light as it passed, in an event dubbed the occultation. When the planet blocked that light, scientists were able to see its ring.
Typically, learning from occlusions can be difficult because the alignment of the planet, stars and telescope must be perfect, ESA explained.
“When we put it all together, we saw dips in brightness that were not caused by Quaoar but indicated the presence of material in a circular orbit around it,” Bruno Morgado of the Universidade Federal do Rio de Janeiro said in a statement. “The moment we saw that, we were like, ‘Okay, we see a ring around Quaoar.'”
Quaoar is part of a cluster of about 3,000 dwarf planets known as trans-Neptunian objects, found outside the orbit of the planet Neptune.
Scientists are now wondering why the dense material in Quaoar’s ring hasn’t coalesced into a small moon, given the ring itself is “at a distance of almost seven and a half times the radius of Quaoar,” according to ESA.
While rare, Quaoar is not the only dwarf planet to have a ring. Two others, Chariklo and Haumea, were spotted by ground-based observations, according to ESA. However, the placement of Quaoar’s ring makes it more interesting.
Dense ring systems usually exist within a planet’s so-called Roche limit, ESA explained. The Roche limit that exists around a planet or celestial body is the point at which a celestial object around it would be broken into many pieces. For example, as Earth’s moon enters the planet’s Roche limit, it would be expected to merge into many pieces – perhaps a ring.
In the case of Quaoar, its dense ring lies well outside the Roche limit, leading scientists to wonder why it exists as a ring, as opposed to a moon.
“As a result of our observations, the classical notion that dense rings survive only within the Roche limit of a planetary body needs to be thoroughly revised,” said Giovanni Bruno of the National Institute for Astrophysics in Italy.
An early guess as to why Quaoar’s dense ring didn’t form into a moon is due to the freezing temperatures there, ESA said. The cold could prevent the ice particles from sticking together.
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Simrin Singh
Simrin Singh is a social media producer and trending content writer for CBS News.
https://www.cbsnews.com/news/dense-ring-dwarf-planet-quaoar-neptune-unexplained/ Scientists find dense ring around dwarf planet but can’t explain exactly why it’s there