A study finds that stars and planets form and evolve in a coordinated manner
It was previously thought that planets form only when a star reaches its final size
Researchers studied the atmosphere of the remnants of old, faint stars in order to verify the core from which the planets are formed (Reuters)
Astronomers have found that the formation of planets, when the solar system began to form , had begun at a much earlier stage than previously thought. Based on practical research, it has been shown that the main core of planets is forming at the same time, parallel to the parent star.
A study conducted on some of the oldest stars in the universe indicates that some planets, such as Jupiter and Saturn, had begun to form at the same time that the young star was growing.
Previously, it was thought that planets only form once a star reaches its final size, but the new research indicates that stars and planets grow together in parallel.
The researchers assert that the Cambridge University -led study has changed our understanding of how planetary systems, including our solar system, are formed, which could solve a major astronomy puzzle.
First author of the research, Dr Amy Bonsor, from the University of Cambridge's Institute of Astronomy, said: "We had a pretty good idea of how planets form, but a big question we've always had is when do they form? The parent star is still growing, or millions of years later?
To answer the question, the researchers studied the atmospheres of white dwarf stars - the old, fading remnants of stars like our galaxy's sun - in order to investigate the core from which planets form.
And Dr. Bonsor saw that "some white dwarfs are like amazing laboratories for us, because their thin atmosphere is almost like an orbital graveyard (for the remains of faint stars) in outer space."
While a telescope cannot probe the interiors of planets, a special class of white dwarfs - known as polluted systems - contain in their normally clean, transparent atmospheres heavy elements such as magnesium, iron and calcium. These elements are supposed to have come from small bodies such as asteroids formed by the formation of planets, which collided with white dwarfs and burned in their atmosphere.
From here, observations of polluted white dwarfs can explore the interiors of these fragmented asteroids, which opens a direct door for astronomers to gain insight into the conditions under which they formed.
In this context, scientists analyzed data collected from the atmospheres of about 200 polluted white dwarf stars emanating from neighboring galaxies.
According to their findings, the mixture of elements seen in the atmosphere of those white dwarfs can only be explained if a large number of the original asteroids have completely melted. This would have caused the heavy iron to precipitate and permeate its interior and the lighter elements to come out to the surface.
This process, known as differentiation (the transformation of the Earth from a randomly mixed mass of material into a body divided internally into concentric shells that differ physically and chemically) enabled the Earth to form an iron-rich core.
Dr. Bonsor points out that “the cause of the melting can only be attributed to the radioactive elements of limited duration, which were present in the early stages of the planetary system, but they vanish within only a million years. In other words, if these asteroids were melted by elements that exist only for a period.” So brief in the dawn of the planetary system, planet formation must have started at a rapid pace."
The study says that the theory of the early formation of the planets is likely to be correct, which means that Jupiter and Saturn had plenty of time to grow until they reached their current sizes.
"This is just the beginning - every time we find a new white dwarf star, we can collect more evidence, and learn more about how planets form. We can then track elements such as nickel and chromium, and determine how big the asteroid was when it formed its core," Bonsor explains. of iron.”
"It is amazing that we are able to investigate processes like this within exoplanet systems," she concludes.
The study, which also involved researchers from the British University of Oxford , the German Ludwig Maximilian University in Munich, the Dutch University of Groningen, and the Max Planck Institute for Solar System Research in Göttingen, Germany, was published in the scientific journal Nature Astronomy.
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