Milky Way star disk it's not stable and flat. Instead, it becomes getting "disabled" and rotate far from the center of the Milky Way. These are the conclusions of astronomers from the National Astronomy Observatory of the Chinese Academy of Sciences (NAOC).
From a great distance, the galaxy will look like thin star discs that orbit once every few hundreds of millions of years around its central region, where hundreds of billions of stars, along with large amounts of dark matter, provide gravity "glue" to maintain everything.
But the power of gravity it weakens far from the internal region of the Milky Way. In the galactic outer disks, the hydrogen atoms that make up most of the Milky Way's gas discs are no longer confined to thin fields, but are given to discs S's appearance is distorted.
"It is very difficult to determine the distance from the Sun to the part of the gas disc outside the Milky Way without having a clear idea of what the disc is like," said the NAOC researcher. Chen Xiaodian, lead author of the article published this Monday at Natural Astronomy.
"However, we recently published a new catalog of star correct behavior variables known as Classic Cepheids, for which you can determine the right distance like 3 to 5 percent. "The database allows the team to develop first three-dimensional image right from the Milky Way in the most remote area.
Classic Cepheids are young star that from four to 20 times bigger than our Sun. and upwards 100,000 times brighter. The mass of stars as high as that implies that they live fast and die young, burn their nuclear fuel very quickly, sometimes only in a few million years. They showed vibrations from one day to the next, which were observed as changes in brightness. Combined with the brightness observed from Cepheid, the pulsation period can be used to obtain very reliable distances.
"To our surprise, we found that in our 3D collection of 1,339 Cepheid stars and gas discs from the Milky Way were closely monitored, offering a new perspective on the formation of our galaxy," said the professor. Richard de Grijs, from the University of Macquarie, in Sydney, Australia, and the lead author of this article. "Perhaps most importantly, in areas outside the Milky Way, we found that S-type star discs transformed into progressively bent spiral patterns," he added.
This reminded the team of previous observations of a dozen other galaxies that also showed increasingly twisted spiral patterns. "Combining our results with these other observations, we conclude that the Milky Way's spiral pattern might be caused by" torque "(or force) by large internal discs," Dr. Liu Chao, principal researcher and co-author of this paper.
"This new morphology provides important maps that are updated for the study of our galaxy star movements and the origin of the Milky Way discs," added Dr. Deng Licai, NAOC principal investigator and co-author of the article.