Researchers define the border of the Milky Way at 40 thousand light years with data from the Gaia satellite

An international group of scientists has defined the exact frontier of Via Láctea regarding its ability to generate new celestial bodies. The limit of our galaxy’s star-forming region is between 35,000 and 40,000 light-years away from the galactic center. The discovery ends decades of uncertainty about the real size of the structure that houses Sistema Solar.

The unprecedented mapping required the analysis of information from more than 100,000 giant stars spread across space. Researchers have crossed ultra-precise position and motion measurements with advanced simulations of cosmic evolution. The result of the work was published in the scientific journal Astronomy & Astrophysics. The new measurement changes fundamental understanding about the dynamics of our own address in the universe.

Desafio to map the galactic structure from the inside out

Observing Via Láctea imposes a natural physical barrier to ground-based astronomers. Estudar galaxies located millions of light years away is usually a simpler task than analyzing our own neighborhood. The planet Terra is buried in the galactic disk. Tentar drawing the contours of this structure is equivalent to mapping a dense forest without being able to leave the trees. Nuvens thick layers of interstellar gas and dust block the view of telescopes in many directions.

Apesar of visual obstacles, recent technology has enabled significant advances in space exploration. Scientists managed to record the first image of the supermassive black hole Sagitário A*, located in the nucleus of the galaxy. The teams also identified that the galactic disk presents folds and distortions at the edges, discarding the idea of ​​a perfectly flat spiral. Faltava discover the exact point where the galaxy loses the ability to condense material to ignite new suns.

Stars’ Idade Reveals Exact Breakpoint

The solution to the mystery came from analyzing the age of the stars distributed across the disk. Researcher Karl Fiteni, of Universidade of Insubria, at Itália, led the investigation that identified a clear mathematical pattern. Spiral galaxies grow from the inside out during their evolution. The core concentrates the oldest stars in the system. Conforme the distance from the center increases, the average age of the stars progressively decreases.

The expected behavior underwent a sudden change at the mark of 40 thousand light years away from the nucleus. The stellar rejuvenation trend completely disappeared at this point. Stars located beyond this border began to record much older ages. The distribution graph formed a U-shaped curve. The lowest point of this line marked the exact boundary of Via Láctea’s star factory.

Para To achieve this level of precision, the international team used a combination of cutting-edge technological tools:

• The European Gaia satellite provided three-dimensional mapping of billions of celestial bodies with unprecedented astrometric precision.
• The LAMOST and APOGEE observation programs delivered detailed spectrographic data on the chemical composition of the stars.
• Supercomputadores processed N-body simulations to model the gravitational evolution of the system over billions of years.

The integration of these three pillars of data made it possible to isolate the behavior of giant stars in the most distant and dark margins of the galactic disk.

Migração radial pushes ancient stars to the edges

The presence of old stars in a distant region has raised new questions for researchers. The answer to the phenomenon lies in a mechanical process known as stellar radial migration. The stars found on the edges of Via Láctea did not form in those extreme coordinates. Eles were born in the central and dense regions of the galaxy. The gravitational interaction with the spiral arms pushed these celestial bodies outwards in a slow and steady manner.

The movement works like an ocean wave that gradually carries objects away from the origin. Victor P. Debattista, Universidade researcher of Lancashire, pointed out that stars in the outer disk maintain nearly circular orbits. The orbital characteristic proves that the stars belong to the original disk and did not get there through collisions with satellite galaxies. The journey requires billions of years to complete. Apenas the oldest stars have had enough time to reach the 40,000 light-year boundary.

Researcher João A. S. Amarante, from Universidade Jiao Tong of Xangai, highlighted the importance of virtual modeling in the study. The simulations proved that stellar migration changes the age profile of the galactic disk in a predictable way. Mathematical models confirmed the observations made by the telescopes.

Hipóteses on blocking new star births

Scientists are now investigating the reasons why star formation abruptly stops at the mapped boundary. The astronomical community works with three main hypotheses to explain the phenomenon. The first suggests that Via Láctea’s central bar acts as a physical blockage against the flow of gas necessary for star creation. The second theory points to gravitational deformations at the edges of the galactic plane. The third possibility indicates that the gas in the outer region reaches an extreme level of rarefaction. The material cannot cool enough to collapse and generate nuclear ignition.

Researcher Joseph Caruana, from Universidade and Malta, assesses that the volume of data processed ushers in an unprecedented phase in modern astronomy. Combining real observations with massive computing power makes it possible to test old theories with mathematical precision. The arrival of new observation instruments promises to accelerate the pace of discoveries.

The 4MOST and WEAVE astronomical programs will come into operation in the coming years to expand data collection. The equipment will analyze billions of additional stars in the darkest regions of the galaxy. The information will refine estimates of the age and proper motion of celestial bodies. The 40,000 light-year limit establishes a new ground zero for understanding the evolutionary dynamics of spiral galaxies across the universe.