For centuries, astronomers have studied the Milky Way to better understand its size and structure. And while modern instruments give invaluable observations to our galaxy and others (which allowed astronomers to get a general picture of what it looks like), a truly accurate model of our galaxy is elusive.
For example, a recent study by a team of astronomers from the The National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) have shown that the Milky Way disk is not flat (as previously thought). Based on their findings, it seems that the Milky Way is becoming more distorted and distorted as the farther goes out of the core.
The study, which details their findings, has recently appeared in the scientific journal Nature, "Intuitive 3D Map of the Galactic Base Precession Traceable by Classical Cepheids." Normal University.
In order to destroy it, galaxies such as the Milky Way consist of thin discs of stars that circle around the central bulge once every hundred million years. In this bulge, the gravitational force of hundreds of billions of stars and dark matter together hold the matter and gas of the galaxy. However, in the distant outer regions of the galaxy, the hydrogen atoms making up the bulk of the gas disc are no longer limited to a thin plane.
As Dr. Chen explains in one of the latest statements of the Institute at the University of Kuala Lumpur:
"It is known that it is difficult to determine the distances from the Sun to parts of the Milky Way external gas disk without having a clear idea of what this disk really is. However, we have recently published a new catalog of periodic variable stars, known as classic cefeids, for which distances with an accuracy of 3 to 5% can be determined. "
Classic Cephieds are a subclass of Cephied variables, a star type that is noted for the way it regularly pulsates, varying in diameter and temperature. This results in brightness changes that are predictable in terms of period and amplitude and makes them extremely useful for measuring galactic and cosmic distances.
Classic cefeids are a peculiar kind of young yellow bright giants and supergiants that are 4 to 20 times more massive than our Sun and up to 100,000 times lighter. This means they have a short shelf life, which sometimes lasts only a few million years before it exhausts its fuel. They also experience ripple that can last for days or even months, making them very reliable for measuring distances to other galaxies.
As Dr. Shu Vang, from the Institute of Astronomy and Astrophysics, Cavly and co-author of the article, said:
"Much of the Milky Way is hidden from dust, making it difficult to measure distances to the stars. Fortunately, observations of long infrared wavelengths can circumvent this problem."
For the purpose of their research, the team created a 3D model of the Galactic Disc, based on the positions of 1339 classical Cephieds. From this they can prove that the galactic disc is not in line with the galactic center. In fact, when viewed from above, the Milky Way disk will look S-shaped, with one side curving upward and the other curving down.
University Professor Said McCoory Richard de Grees, Senior Co-author of the report:
"Somewhat to our surprise we found that in our 3D Cesheid stars and the Milky Way Gas Drive are closely monitored. This offers new insights into the formation of our home galaxy. Perhaps more importantly, in the outer regions of the Milky Way we have found that the S-shaped star disk is distorted in a progressively twisted spiral. "
These findings recall what astronomers have observed from a dozen other galaxies that show progressively twisted spiral patterns. By combining the results with these observations, the researchers concluded that the spiral model of the Milky Way is most likely caused by a rotary forcing (also known as "torque") on the internal disk.
This latest study has provided an up-to-date map of the star movement of our galaxy that would shed light on the origin of the Milky Way. Moreover, it can also inform our understanding of the formation of galaxies and the evolution of space.
Further Reading: Institute of Astronomy and Astrophysics, Kavli