Over the centuries, astronomers have studied the Milky Way to gain a better understanding of its size and structure. And…
Over the centuries, astronomers have studied the Milky Way to gain a better understanding of its size and structure. And although modern instruments have provided invaluable observations of our galaxy and others (which have allowed astronomers to get a general idea of what it looks like), a truly accurate model of our galaxy has been uneven.
For example, a new study by a team of astronomers from the National Astronomical Observatories of Chinese Academy of Sciences (NAOC) has shown that the milk disk is not flat (as previously thought). Based on their results, it seems that the Milky Way becomes more and more twisted and twisted further away a bet from the core.
The study describing their findings recently appeared in the scientific journal Nature, titled “An intuitive 3D map of Galactic warp precession is tracked by classic Cepheids.” The study was led by Xiaodian Chen of NAOC’s Key Laboratory for Optical Astronomy, and included members of the Kavli Institute for Astronomy and Astrophysics at Peking University and China West Normal University.
Using information from Gaia’s second data release, a team of researchers has made refined estimates of the Milky Way mass. Credit: ESA / Gaia / DPAC
To break it down, galaxies are like the Milky Way of thin slabs of stars revolving around a central lane once a hundred million years. In this bulge, the gravitational force of hundreds of billions of stars and dark matter holds the matter and gas of the galaxy together. But in the outermost regions of the galaxy, hydrogen atoms that make up the bulk of the gas disc are no longer limited to a thin plane.
As Dr. Chen explained in a newsletter from the Kavli Institute:
” It is remarkably difficult to determine distances from the sun to parts of the Milky Way’s outer gas plate without having a clear idea of what that disc actually looks like. However, we recently published a new directory of periodic variable stars called Classical Cepness, for which distances are as accurate as 3 to 5% can be determined . “
Classic cephieds are a subclass of Cephied Variables, a type of star noted for how it pulses regularly, varying in both diameter and temperature. This provides changes in brightness that are predictable in terms of period and amplitude and make them very useful for measuring galactic and cosmic distances.
The Milky Way, disturbed by the tidal interaction with a dwarf galaxy, as predicted by N-body simulations. Credit: T. Mueller / C. Laporte / NASA / JPL-Caletch
Classic Cepheids are a special type of young yellow bright giants and supergiants that are 4 to 20 times as massive as our Sun and up to 100,000 times bright. This means that they have short lifetimes, which sometimes last only a few million years before they extinguish their fuel. They also experience pulsations that can last days or even a month, making them very reliable for measuring distances to other galaxies.
As Dr. Shu Wang, by the Kavli Institute for Astronomy and Astrophysics and co-author on paper, states:
” Much of our Winter Street is hidden by dust, making it difficult to measure distances to stars. Fortunately, observations at long infrared wavelengths circumvent this problem. “
For their studies, the team founded a 3D Galactic Disk model based on the positions of 1,339 classic cephieds. From this, they could provide strong evidence that the galactic disc is not in line with the galactic center. In fact, the wavy sheet actually looks like a S-shaped top, with one bent and the other bent.
Three-dimensional distribution of the classic Cepheid variable stars in the Milky Way’s turntable (red and blue) centered on Sun’s location (shown as a large orange symbol). Credit: Chen Xiaodian / Kavli Institute of Astronomy and Astrophysics
Sajde Macquarie University’s Professor Richard de Grijs, a senior co-author on the paper:
“Something to our surprise we found that in 3D our Cepheid stars and Milk’s gas disk This gives new insights into the formation of our home galaxy. Perhaps more importantly, in the outer areas of the milk, we found that the S-like star disk is interspersed with a progressively twisted spiral pattern. “
These findings resemble which astronomers which has observed a dozen other galaxies, which showed progressively oblique spiral patterns. By combing their results with these observations, the researchers concluded that the spiral pattern of the milk is probably caused by the torque on the inner disc.
The latest study has given an updated map of our galaxy star performances, which would shed light on the origins of the Milky Way. In addition, it can also inform our understanding of galaxy formation and the development of cosmos.