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The Milky Way Is Warped

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Astronomers have used 1339 “standard” stars to map the real shape of our home galaxy. They found the Milky Way’s disc of stars becomes increasingly “warped” and twisted like an “S” the further away the stars are from the galaxy’s centre. “We usually think of spiral galaxies as being quite flat like Andromeda,” says Prof Richard de Grijs of Macquarie University, who co-authored the paper published in Nature Astronomy (https://goo.gl/67EoXQ).

The researchers were able to determine our galaxy’s S-shaped appearance after they developed the first accurate three-dimensional picture of the Milky Way to its far outer regions.

“It is notoriously difficult to determine distances from the Sun to parts of the Milky Way’s outer gas disc without having a clear idea of what that disc actually looks like,” says Xiaodian Chen of the Chinese Academy of Sciences in Beijing, who was lead author of the paper. “However, we recently published a new catalogue of well-behaved variable stars known as classical Cepheids, for which very accurate distances can be determined with an error of only 3–5%.”

Classical Cepheids are young stars that are four to 20 times as massive as our Sun and up to 100,000 times as bright. Such high stellar masses imply that they live fast and die young, burning through their fuel...

The full text of this article can be purchased from Informit.