It is estimated that the Milky Way contains about 400 billion stars. Knowing that there are billions of other galaxies in the universe, we can consider the existence of more than 10 sextillion stars in the sky.
Recently, the Digital look Reported that the European Space Agency (ESA), through the Gaia mission, created the most detailed 3D map of the Milky Way. To get both this position chart and the others already designed, the astronomers had to deal with the same problem: the red supergiants.
In fact, such stars have a behavior that is difficult to define correctly: they bubble and foam so much that they seem to dance around their positions in space. According to the website PhysicalThis oscillation is a feature of these ancient stars, not an inconsistency.
It’s not for nothing that they get the nickname “Supergiants”. These stars are huge: they are 700 to 1,000 times the diameter of the sun and at least eight times the mass of the sun – however, they are cooler than the stars.
Supergiants are much brighter in infrared light, but weaker in visible light than other stars. These also vary in their brightness, which (for some of them) may be related to this dance performance.
According to researchers, these stars expand so much that they eventually reach very low surface gravity. As a result, its conductive cells (structures that transport heat from the interior to the surface) become very large, reaching about 30% of the star’s radius, and “breaking” its brightness.
Circulation not only transfers heat from the inside to the outside, it also helps the star to emit material into nearby space. And it doesn’t happen as a slight gas and plasma splash.
A red supergiant can send a billion times more mass into space than the Sun. As a result of all these actions foamy stars appear, its bubble surface. The movements caused by this process form the “dance” of the heavenly body around its “home” in space.
The ballet caused by the boiling of the circulating cell, as well as the accumulation of ejecta around the star, increases its variability, which affects its brightness over time.
One of the methods used by astronomers to determine the exact position of a star is to use its “photographic center”. It is the center of starlight. If the brightness of the star changes (for any reason), this point is removed.
Understands why the red supergiants “dance”
Andrea Chiavasa, a scientist from the Labrador’s Lagrange, the Excelenzcluster Origins, and the Max Planck Institute for Astrophysics, and a researcher at the Munich Observatory and the Hawaii Institute, led by a team of astronomers, Ralph Kudritsky. The red supergiants
“Synthetic maps show highly irregular surfaces, where larger structures evolve over months or even years, while smaller structures evolve over weeks,” Chiavasa says. “This indicates that the position of the stars must change over time.
In their study published in the journal Astronomy and astrophysicsThe team compared their model to the constellation of Chi Persi, a cluster of constellations of Perseus, which was measured by the Gaia satellite, so most of its stars are very precise – except for the red supergiant.
“We have seen that the positional uncertainty of red supergiants is much higher than that of other stars. This ensures that their surface structure changes significantly over time as predicted by our calculations, ”Kudritzki explained.
Knowing how the stars dance shows a way to calculate their distance. Future models will help astronomers refine these distances and provide more information about what will happen to these stars as they age.
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