The star disc of the Milky Way this is anything but stableOn the contrary, it happens increasingly deformed and twisted away from the center of the Milky Way. This is the conclusion of astronomers from the National Astronomical Observatories of the Chinese Academy of Sciences.
From a long distance the galaxy will look like this a thin disk of stars this orbit once every few hundreds of millions of years around its central area, where hundreds of billions of stars, along with a large mass of dark matter, provide The "glue", gravitational, to keep everything together,
But the power of gravity it weakens away from the inner regions of the Milky Way. In the far outer disk of the galaxy, the hydrogen atoms, which make up the bulk of the Milky Way gas disc, are no longer limited to a thin plane but are given on the disk. distorted appearance,
"It is known that it is difficult to determine the distance from the Sun to parts of the Milky Way external gas disc without having a clear idea of what this disk looks like," says the NAOC researcher. Chen Xiaodian, chief author of the article, published this Monday at Nature Astronomy,
However, we have recently published a new catalog of the right behavioral variable stars, known as Classic cefeids, for which you can set as precise distances as 3 to 5%. "This database has enabled the team to develop the first three-dimensional image specifically for the Milky Way in the outermost regions.
Classic cefeids are young stars who are from four to 20 times more massive than our Sun and upwards 100,000 times brighter, Such high star masses suggest that they live fast and die young, burning their fuel very quickly, sometimes only for a few million years. They show ripples from one day to the next, which are seen as changes in their brightness. In combination with Cepheid's brightness, its pulsation period can be used to obtain a highly reliable distance.
"To our surprise, we have found that in 3D our 1339 stars Cepheid and the Milky Way gas gauge have been carefully observed, offering new prospects for our galaxy," says the professor. Richard de Greessfrom the University of Macquarie, Sydney, Australia, and co-author of the article. "Perhaps most importantly, in the outer regions of the Milky Way, we find that the S-type star disc is deformed in a progressively twisted spiral pattern," he adds.
This reminded the team of the previous observations of a dozen other galaxies that also show progressively twisted spiral patterns. "Combining our findings with these other observations, we come to the conclusion that the deformed spiral pattern of the Milky Way is probably caused by" torque "(or forced force) from the massive internal disk," said Dr. Liu Chao, a researcher. director and co-author of the article.
"This new morphology provides a crucial updated map for exploring the star movement of our galaxy and the origin of the Milky Way disc," adds Dr. Dunn Lajai, principal investigator and co-author of the article.