Scientists squint past Uranus and see another tiny ring

Mindy Sparks
October 12, 2017

The gas-giant planets in our solar system all have rings, though Saturn's spectacular array is the best known of the bunch.

Thousands of so-called Neptunian objects are located in the outer solar system.

Astronomers spotted the ring by measuring Haumea's size, shape and density as it passed in front of a distant star. No, not Pluto; we're talking about the dwarf planet Haumea.Discovered in 2004, Haumea lies a few billion miles farther from the sun than Pluto.

Until now, ring-like structures had only been found around the four outer planets - Jupiter, Saturn, Uranus and Neptune.

According to the team, Haumea's ring has a width of 70 kilometres (43.5 miles) and a radius of about 2,287 kilometres (1,421 miles), and the dwarf planet rotates three times on its axis in the time that a ring particle completes one revolution.

Haumea is twice as long, maybe longer, in one direction as it is in the other, giving it an appearance sort of like a river rock.

Haumea spins incredibly fast: this is the reason for its odd shape - which has been likened to an elongated egg or flattened rugby ball.

The researchers also discovered the ring's orbital period is three times Haumea's spin period which - at less than four hours - is one of the quickest known.

But Haumea's ring is the first time astronomers have witnessed the phenomenon in a minor planet that isn't a Centaur.

In the solar system rings were believed to be present exclusively around the four gas giants - although only those of Saturn are easily visible from Earth.

In addition to the rings found around Chariklo, there's also evidence of a similar phenomenon around another Centaur called Chiron, although it's less clear than the Chariklo ring.

Artistic concept of Haumea and its ring system with correct proportions for the main body and the ring.

Using that information, the researchers figured out just how big Haumea was. Its diameter is approximately a third of the size of Earth's moon.

Other than Pluto, Haumea is one of the largest objects that orbits the Kuiper Belt beyond Neptune, reported.

It is named after the Hawaiian goddess of fertility and childbirth.

The findings were published Wednesday in the journal Nature.

"Our discovery proves that there is a lot more diversity and imagination in our solar system than we had thought", study co-author Bruno Sicardy of the Paris Observatory told AFP.

Other reports by Iphone Fresh

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