Haumea rotates every four hours. But it gets even weirder.
The presumption that only larger planets like Saturn can host rings has been busted.
The discovery also marks the first time anyone has found rings around an object in the Kuiper belt, a region of icy bodies out beyond the orbit of Neptune. They got 10 Earth-based observatories ready, and on that night all pointed their telescopes towards the same patch of sky to learn as much as they could. Oritz says there is more than one possible answer to that question.
It wasn't just rings that the team were looking out for however, as it also gave astronomers an opportunity to analyse its shape, and it could be about to jeopardise its status as a dwarf planet.
As a bonus, just before and just after Haumea blotted out the star, the telescopes also saw the starlight slightly fade out again: a signature for the presence of a ring. Saturn's rings, for example partly came from Enceladus, one of its 53 moons.
Konstantin Batygin, CalTech planetary astrophysicist, wasn't surprised. In fact, it might be taken out of the "dwarf planets list" that the astronomers composed. It has two known moons: "Hiʻiaka and Namaka". Jose Ortiz of the Institute of Astrophysics of Andalusia in Spain said that it is regrettable that even with the most enormous telescopes on Earth, or the Hubble Space Telescope, we can not see the details of Haumea, than a dot of light. But it appeared that someone at Ortiz's institution had been sifting through famous planet hunter (and Batygin's now-partner) Mike Brown's online notes showing the object just before the announcement. In 2006, it was revealed that some of them could be as large as Pluto, which led the International Astronomical Union to create the category of dwarf planets.
"Prior to our work, researchers thought that Haumea was made mostly of rock and that it had a relatively thin crust of water ice", Ortiz told BuzzFeed News. "This deployment of technical means allowed us to reconstruct with a very high precision the shape and size of dwarf planet Haumea, and discover to our surprise that it is considerably bigger and less reflecting than was previously believed".
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.