We already know that the Sun, in its last great cosmic action, will eventually expand and engulf the Earth, but for smaller and more distant objects, what will our star do? It will be a deadly event, as its light will literally make asteroids … die.
A team of American scientists claims that electromagnetic radiation from stars at the end of their giant asymptotic branch phase (a period of stellar evolution that all intermediate-mass stars undergo at the end of their lives) lasts for a few million millions of years. years and in which they increase their luminosity 10,000 times before collapsing into white dwarfs , it would be strong enough to tear asteroids. As a result, even the asteroid belt of our solar system will be pulverized by the Sun within billions of years.
The new study, published in the journal Monthly Notices of the Royal Astronomical Society, analyzed the number of successive rupture events and the rapidity with which this cascade of events occurs, concluding that, in about six billion years, when the Sun burn the last of your hydrogen reserves and become a red giant, you will eject very powerful streams of energetic particles into space that will be absorbed by asteroids.
Thus, radiation from the star will be absorbed by orbiting asteroids, internally redistributed, and then emitted from a different location, creating an imbalance. This instability creates a torque effect that gradually rotates the asteroid. This is known as the YORP effect, named for four scientists (Yarkovsky, O’Keefe, Radzievskii, Paddack) who contributed ideas to the concept.
Little by little, asteroids will break up into smaller and smaller pieces, as we have seen in other parts of our solar system; The process will repeat itself in several stages, spinning them faster and faster until, about one rotation every two hours, internal stress tears the rocks apart and asteroids break down into smaller and smaller objects (yes, like in the classic game of Atari arcade “Asteroids”) after each destruction event, until they eventually disappear.
“For a giant branch of solar mass, as our Sun will become, even the analogs of the exo-asteroid belt will be completely destroyed. The YORP effect in these systems is very violent and acts rapidly, on the order of a million years. Not only will our own asteroid belt be destroyed, but it will happen quickly and violently. And due solely to the light of our Sun “, clarifies Dimitri Veras, of the Group of Astronomy and Astrophysics at the University of Warwick, and study leader.
The remaining space dust from the pulverized asteroids will be drawn towards the star, already in the form of a white dwarf, like a disk of debris. It is clear that it would be an excellent time to study the pollution around these types of stars, but it would be an impossible task since human beings would have become extinct by then, when our planet had evaporated during the expansion of the Sun.
Referencia: Dimitri Veras et al. Post-main-sequence debris from rotation-induced YORP break-up of small bodies – II. Multiple fissions, internal strengths, and binary production, Monthly Notices of the Royal Astronomical Society (2019). DOI: 10.1093/mnras/stz3565
