The flattest star yet seen is forcing researchers to revise their ideas on the dynamics and structure of celestial bodies. The star, called Achernar, was observed by astronomers at the European Southern Observatory in Chile.
According to standard celestial theories, the fast spinning star should be only 20 to 30 per cent wider across its equator than from pole to pole. But Achernar, which spins at 225 km per second, has a colossal bulge around its equator and is 50 per cent wider.
All stars and planets that reach a critical spin velocity bulge slightly at the equator. The Earth is 40 kilometres, or 0.3 per cent, wider from east to west than from north to south. Astronomers had been confident that their calculations of this oblateness were fairly accurate.
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鈥淏ut the new observation means that the model for fast rotating stars is not complete,鈥� says astronomer Pierre Kervella, one of the team at the European Southern Observatory. 鈥淲e clearly do not know enough.鈥�
鈥淓ither the core is rotating faster than the surface or the star鈥檚 matter is circulating in an unexpected way. We鈥檙e not sure which possibility is correct at the moment,鈥� he told 快猫短视频.
The discovery was made by astronomers using the Very Large Telescope Interferometer at ESO鈥檚 Paranal site in Chile. This uses two 40-centimetre reflecting telescopes to produce images which are then combined and passed through an interferometer. This permits extremely accurate measurements 鈥� the instrument could spot a one euro coin at 2500 kilometres distance.
The astronomers now plan to gather even higher resolution images using a trio of 1.8 metre telescopes. 鈥淏ut our immediate task will be to re-design our computer models,鈥� says Kervella. The team hopes to use the models to distinguish between the two possible explanations for the star鈥檚 extraordinary flatness.