Modeling showed that the Sun, having turned into a red giant, will destroy the asteroid belt and turn into dust all its large bodies.
Under the influence of solar radiation, different parts of the surface of asteroids are heated unevenly. This can lead to changes in their rotation, which will become very significant over time. This phenomenon is called the YORP effect, and as the sun ages, it will manifest itself much more strongly.
Approaching the exhaustion of fuel for the continuation of thermonuclear reactions, solar-type stars move to the branch of red giants, become colder, larger and brighter. Having passed this phase, in a few billion years the Sun will finally become a white dwarf and will remain in this form indefinitely. By that time, his entire environment will be completely different.
"When an ordinary star reaches the giant branch, its luminosity peaks 1,000 to 10,000 times that of the Sun," said Dimitri Veras, astrophysicist at the University of Warwick. - Then the star shrinks to a white dwarf with dimensions of the order of the Earth and fainter than that of the Sun. Therefore, at the stage of the giants, the YORP effect is very important, but then it becomes insignificant."
In an article published in the Monthly Notices of the Royal Astronomical Society, Veras, together with his US colleague Daniel Scheeres, examined the influence of the YORP effect of the future giant Sun on the fate of the asteroid belt located between the orbits of modern Mars and Jupiter. The simulation showed that under the influence of the intensified radiation of the star, asteroids with a diameter of more than 200 meters will spin up to such speeds that they will be torn apart by centrifugal forces.
“The YORP effect in such systems is incredibly strong and fast acting,” adds Dimitri Veras. - Over a period of about a million years, our asteroid belt will not only be destroyed, but will collapse quickly and mercilessly. And all - at the expense of only one sunlight”.
Such a fate, apparently, is met by similar asteroid structures in other stellar systems similar to ours. Scientists notice that the spectra of many white dwarfs contain lines of "metals" that are close in composition to the matter of asteroids. The results of the new work make it possible to explain this feature.
Apparently, such white dwarfs had rather massive asteroid belts, however, passing along the branch of giants, they destroyed them. Part of it remained in orbit by a scattered dust cloud, and part was absorbed, giving the half-dead white dwarf some "spectral features" of dead asteroids.