Astronomers have discovered a dwarf planet in the Solar system ring

Egg-shaped Haumea was discovered in 2004 but astronomers have just been able to establish that it has a ring. Image credit- IAA-CSIC UHU

Egg-shaped Haumea was discovered in 2004 but astronomers have just been able to establish that it has a ring. Image credit- IAA-CSIC UHU

The new measurements confirmed Haumea's density - slightly lower than we thought - but its odd shape means its gravity is not strong enough to make itself round, which could see it miss out on the criteria set out for a cosmic body to be named a dwarf planet. It seems that scientists keep discovering other objects - and not planets - that are being rounded by rings.

This recent discovery implies that there might be more small bodies in the outer Solar System surrounded by rings, and humans simply haven't been able to determine every single one of them yet.

They say the dwarf planet has an unusual elongated ellipsoid shape, with axes of approximately 2,322 kilometres (1,442 miles) by 1,704 kilometres (1,059 miles) by 1,138 kilometres (707 miles), and no global atmosphere that can be detected.

The ring was spotted in the pattern of light from the star Haumea occluded, and the Nature paper says the rings are similar to those that surround Uranus and Neptune.

Ortiz's team has put together a YouTube visualisation of the rings, below.

The peculiar dwarf planet Haumea has just gotten more peculiar with the discovery of some faint rings around it. In fact, it might be taken out of the "dwarf planets list" that the astronomers composed.

Beyond the orbit of Neptune there are hundreds or even thousands of mysterious dwarf planets, most of which we know nearly nothing about - but there's a lot to learn when we catch a rare glimpse. The total number of officially recognised dwarf planets is now five, but some astronomers argue there could be hundreds of objects in the solar system that fit the definition. When Haumea passed in front of a star called URAT1 533-182543 on January 21 of this year, scientists were able to view the dwarf planet with 12 telescopes from ten different labs.

The rings could be key to figuring out Haumea's history.

Haumea's ring is less reflective than the dwarf planet's bright water ice surface, suggesting it is made up of a mixture of rock and ice. Ortiz estimates that about a quarter of bodies in the outer solar system might have rings around them, although he stresses that this is still "pure speculation" for now.

The finding of rings also suggests that Haumea might have been hit with something not long ago, at least in terms of space, possibly between 700m and 1bn years ago.

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