Combined with a Cepheid’s observed brightness, its pulsation period can be used to obtain a highly reliable distance. They show day- to month-long pulsations, which are observed as changes in their brightness. Such high stellar masses imply that they live fast and die young, burning through their nuclear fuel very quickly, sometimes in only a few million years. “However, we recently published a new catalogue of well-behaved variable stars known as classical Cepheids, for which distances as accurate as 3 to 5 per cent can be determined.” That database allowed the team to develop the first accurate three-dimensional picture of our Milky Way out to its far outer regions.Ĭlassical Cepheids are young stars that are some four to 20 times as massive as our Sun and up to 100,000 times as bright. “It is notoriously difficult to determine distances from the sun to parts of the Milky Way’s outer gas disk without having a clear idea of what that disk actually looks like,” says Xiaodian Chen, a researcher at the Chinese Academy of Sciences in Beijing and lead author of the article in Nature Astronomy. In the galaxy’s far outer disk, the hydrogen atoms making up most of the Milky Way’s gas disk are no longer confined to a thin plane, but they give the disk an S-like, warped appearance. Instead, it becomes increasingly ‘warped’ and twisted far away from the Milky Way’s center, according to astronomers from Macquarie University and the Chinese Academy of Sciences, who have built the first accurate 3D map of Earth’s home galaxy and unveiled in a paper published in Nature Astronomy.įrom a great distance, our galaxy would look like a thin disk of stars that orbit once every few hundred million years around its central region, where hundreds of billions of stars provide the gravitational ‘glue’ to hold it all together.īut the pull of gravity becomes weaker far away from the Milky Way’s inner regions.
Our Milky Way galaxy’s disk of stars is anything but stable and flat.
0 kommentar(er)
