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The Milky Way is actually deformed

For centuries, astronomers studied the Roman road to better understand its size and structure. While modern instruments have provided invaluable observation of our galaxy and others (which enabled astronomers to gain a general picture of what it looks like), the genuinely precise model of our galaxy was unavailable.

For example, a recent study of a group of astronomers from. T National astronomical observatories of the Chinese Academy of Sciences (NAOC) have shown that the Milky Way disk is not exactly (as previously thought). According to their findings, it seems that the Roman road is increasingly tense and distorted when it is more distant from the center.

The study, which details their findings, was published in a scientific journal Nature, The study was led by Xiaodian Chen of NAOC's key laboratory for optical astronomy and included members of the Institute of Astronomy and Astrophysics at the Kawli University of Beijing and China in the West. Normal University.

Using data from another Gaia data release, a group of scientists prepared more accurate estimates of the mass of the Milky Way. Credit: ESA / Gaia / DPAC

The galaxies, such as the Roman Road, are made up of thin discs of stars that circulate around the central bulge every few hundred million years. In this projection, the gravitational force of hundreds of billions of stars and dark matter holds together a galaxy and gas. However, in the distant parts of the galaxy, hydrogen atoms that form the majority of the gas surface are no longer confined to a thin plane.

As explained by dr. Chen in a recent statement to reporters Kavli Institute:

"It is known that it is difficult to determine the distances from the Sun to the parts of the external gas plate of the Roman Road without having a clear idea of ​​how this disk actually looks. However, we have recently published a new catalog of periodic variables, known as classical cefeides, for which it is possible to determine distances from 3 to 5%.. «

Classic Cephiedi is a subclass of Cephied variables, a type of star known in the way it regularly pulses and changes in both diameter and temperature. This causes changes in brightness that are predictable in terms of period and amplitude and are very useful for measuring galactic and cosmic distances.

Galaxy Rimska gama, interfered with by tidal interaction with the ground galaxy, as predicted by the N-body simulation. Credit: T. Mueller / C. Laporte / NASA / JPL-Caletch

Classical cepheids are a special type of young yellow light giants and supergiant, which are four to twenty times larger than our Sun and are brighter to 100,000 times. This means that they have short life expectancies that sometimes last only a few million years before they consume fuel. They also experience flashing, which can last for several days or even a month, making them very reliable for measuring distances to other galaxies.

As Dr. Shu Wang from Institute of Astronomy and Astrophysics Kavli and co-author on paper stated:

"Many of our Roman roads are hidden by dust, making it difficult to measure distances to the stars. Fortunately, observations on long infrared wavelengths can overcome this problem."

Due to their study, the team set up a 3D Galactic 3D model based on the 1,339 classic Cephiedov positions. From this they can provide solid evidence that the galactic disc is not in accordance with the galactic center. In fact, when looking up from the top, the Milky Way disc appeared in the shape of a letter S, with one side swinging upward and the other turning downwards.

Three-dimensional distribution of Cepheid's classic variable stars in a distorted disc of the Roman road (red and blue points) with a center at the site of the Sun (shown as a large orange symbol). Credit: Chen Xiaodian / Kavli Institute of Astronomy and Astrophysics

Professor Richard De Grijs, Said Macquarie University, Senior Co-author on Paper:

"To our surprise, we have found that our 3D Cepheid stars and the Roman Roads gamble in 3D are changing sharply. This gives a new insight into the formation of our home galaxy. Perhaps more importantly, in the outer parts of the Roman Road, we found that the S-like star disk was bent in progressively wrapped spiral patterns. "

These findings reminisce of what astronomers have noticed on a dozen other galaxies that have shown gradually twisted spiral patterns. By combining the results with these observations, the researchers concluded that the spiral pattern of the Roman Road is most likely due to rotational force (called "torques") of the internal disk.

This latest study has provided an updated map of the star movements of our galaxy that would illuminate the origin of the Milky Way. Moreover, this could also contribute to understanding the formation of galaxies and the evolution of the cosmos.

Further reading: Kavli Institute for Astronomy and Astrophysics, Nature

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