2021-06-15

Research predicts that after billions of years of harmonious operation, the distant star system will end in chaos

By yqqlm yqqlm

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Research predicts that after billions of years of harmonious operation, the distant star system will end in chaos

The HR 8799 star system is located in the constellation Pegasus, 135 million light-years away. At the center of this system, there is a 30-40 million-year-old A-type star, orbiting it is a pair of debris fields and four massive planets, each of which is more than five times the size of Jupiter.

In millions of years, the gravitational influence of the parent star and each planet caused these four alien worlds to fall into a subtle synchronous orbital pattern called resonance.

In HR 8799, the third planet from the star completed two complete orbits within the time of the outermost planet completing one orbit. As we get closer and closer to the star, this pattern continues. The second planet closest to the star completed four orbits, and the innermost world completed eight in the time the outermost planet completed one orbit. track. In other words, each successive world completes twice as many orbits as its external neighbors.

A team of scientists from the University of Exeter and the University of Warwick in the UK set out to determine the ultimate fate of this unusual system and see what factors would eventually disrupt its unique orbital resonance mode.

For this, the team created an advanced computer model of HR 8799. The simulation takes into account the gravitational influence of the five main stellar system objects, as well as the usual external gravitational forces that affect the planets in the star system, including the galaxy’s tides and the close passage of other stellar objects.

The research team concluded that this resonance may continue for the next 3 billion years, and external influences are rarely strong enough to break the orbital resonance of the planets in the star system. However, the data also shows that this resonance will definitely end when the parent star exhausts its internal hydrogen supply and begins to transform into a huge red giant star.

During this process, the star throws out a lot of mass, which changes its gravitational characteristics and causes the surrounding system to fall into chaos. At this point, the orbits of the surrounding planets will begin to change, as they respond to changing stars, and as the resonance breaks, the gravitational influence of their neighboring world will begin to change.

“They are so big, so close to each other, and now the only reason for them to maintain this perfect rhythm is their orbital position,” the lead author of the new study, Dimitri Veras of the University of Warwick The doctor explained. “All four are connected in this chain. Once the stars lose their mass, their positions will deviate, and then two of them will disperse from each other, causing a chain reaction in all four stars.”

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p >According to computer modeling, this chaotic process usually causes two of the planets to be completely thrown out of the system. The remaining two planets may then stabilize anywhere from 1 AU to thousands of AU from the newly transformed red star.

The simulation results also help explain why astronomers have observed unexpected fragments in the light signals of white dwarfs, which are the late evolution of red giant stars. According to the authors of the study, the chaotic motion of the planet is likely to move matter away from the debris ring, causing it to roll inward and then be absorbed.

This paper has been published in the Monthly Bulletin of the Royal Astronomical Society.