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A new 3D map of the Milky Way shows its twisted and folded shape

Although it has been studied by astrophysicists for many decades, our galaxy, the Milky Way, has not yet revealed all its secrets. Earlier this year, a large study found that the Milky Way was actually not a flat, even disk, but had a twisted shape on its periphery. Recently, researchers have compiled the most accurate 3D map of the morphology of our galaxy, revealing its folded and deformed structure.

Astronomers calculated the distance by calculating the distance between the Sun and thousands of stars in the Milky Way Now we have mapped our galaxy in 3D on a larger scale than ever before. These new findings, published in the journal Science shed light on the twisted and distorted shape of the galaxy disk.

The Milky Way is a spiral galaxy consisting of a central region in the form of a bar, surrounded by a flat disk of gas, dust and stars, about 1

20,000 light years wide. Our solar system is located approximately 27,000 light-years from the galactic center in one of the four spiral arms of the disk.

Much of the current knowledge about the shape and structure of the Milky Way is based on the distances between the Sun and various celestial marks, supported by an extrapolation of what astronomers have seen in other galaxies. However, the distances between the sun and these landmarks are usually measured indirectly.

A galactic map based on the observation of Cepheid stars Sun and a large sample of stars to create a 3D map of the galaxy. They focused on a particular star type known as the Cepheid variable. Cepheids are young supergiant stars that are hundreds of thousands of times brighter than the sun and whose light pulsation rhythm is known.

  simulations Cepheides galaxy

On the left a simulation of the distribution of Cepheid stars in the Milky Way; on the right the result of direct observation of Cepheids. The youngest stars are blue and the oldest ones are marked in red. Crystals: J. Skowron / OGLE / Astronomical Observatory

Cepheids seem to pulsate because their gas heats and cools in very regular cycles, expanding and contracting, which can take several hours to several months. Through the well-defined relationship between the brightness of a Cepheid and its pulsation cycle, astronomers can calculate the intrinsic brightness of a Cepheid by measuring its pulsations.

After Comparing the Self-luminosity of a Cepheid Astronomers can then estimate the distance between Cepheid and our planet by the apparent brightness – that is, by the brightness of the Earth. Astrophysicists can thus determine the distances with these stars with an accuracy of more than 5%.

Thanks to the Optical Gravitational Lensing Experiment which monitors the luminosity of almost 2 billion stars, researchers have mapped the distance between the Sun and more than 2,400 Cepheids across the Milky Way.

" It took six years, but it paid off ," says Astrophysicist of the University of Warsaw, Dorota Skowron, lead author of the study. These discoveries helped astronomers to create a large-scale 3D map of the Milky Way. This is the first map of this type based on distances measured directly to thousands of Celestial Landmarks in the galaxy.

The Milky Way: A Galaxy with Deformed Morphology

The new map allows to reveal more details about the distortions that astronomers had previously discovered. Specifically, the galaxy's disk is not flat but deformed at distances greater than 25,000 light-years from the galactic core. This deformation may be caused by galaxies interacting with satellite galaxies, intergalactic gas, or dark matter.

  Galaxy deformation

Diagram showing the galactic deformation indicated by observation Cepheids. Credits: J. Skowron / OGLE / Observatory

" Deformation of the galactic disk has already been detected, but it is the first time that we can use individual objects to trace their shape in three dimensions [19459007SpeakedPrzemekMrózvonderWarschauerUniversityThedeformationthatresearchersinMilkyWaylookedatwassurprisingly[AfteralltheMilkyWayisnotaflatanduniformdisk

Astronomers are able to deduce the age of the Cepheids in their function of their pulsation cycles and found groups of Cepheids of very similar age. " This is a clear indication that they formed together. We can see with our own eyes and in our own galaxy that the formation of stars is not constant but actually occurs in outbursts "Skowron

  explains from galaxies-Cepheids

Map of the Milky Way with the distribution of the observed cepheid stars showing the twisted shape of the galaxy Credits: J. Skowron / OGLE / Observatory

Stars may have formed as a group after various triggers: Huge interstellar gas clouds may be under their own gravity Splintering and falling into pockets that form stars Fusion between supernova galaxies or interstellar winds can also cause huge clouds to divide into stars.

Accurate galactic 3D maps to better understand the Milky Way

The researchers are planning to refine their 3D map of the Milky Way by taking the distances between the sun and other to draw pulsating stars like RR Lyrae. Like the Cepheids, the RR Lyrae pulsates in cycles of predictable duration, but has existed in the galaxy for much longer. This would help researchers to understand how the older parts of the galaxy have changed over time.

Milky Way's better 3D maps can help astrophysicists better understand their shape. For example, " still discusses the number of main spiral arms and the degree of spiraling of the arms ," Skowron said

A better understanding of the shape of the galaxy could then shed some light on its evolution, for example The way in which stars move and move propagate from their place of origin and what could have deformed the galaxy in the first place.

In this video, astrophysicists explain how they mapped the Milky Way thanks to Cepheids:

Sources: Science

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