Four planets locked in perfect rhythm around a nearby star are destined to be freaked out around their solar system when their sun eventually dies, according to a study by the University of Warwick that looks at its future.
Astronomers modeled how the change in gravitational forces in the system resulting from the star’s transformation into a white dwarf will cause its planets to break away from their orbits and bounce off each other’s gravity, like balls bouncing off a bumper in a pinball game. .
In the process, they’ll hurl nearby debris into their dying sun, giving scientists new insight into how the white dwarfs with polluted atmospheres we see today originally evolved. The findings of astronomers from the University of Warwick and the University of Exeter are published in the Monthly notices from the Royal Astronomical Society.
The HR 8799 system is 135 light years away and includes a 30-40 million-year-old Type A star and four unusually massive planets, all more than five times the mass of Jupiter, orbiting very close to each other. other. The system also contains two debris disks, inside the orbit of the innermost planet and one outside of the outermost planet. Recent research has shown that the four planets are locked in a perfect rhythm which sees each complete double the orbit of its neighbor: thus, for each orbit, the farthest complete, the next closest complete two, the next completes four, while the nearest completes eight. .
The Warwick and Exeter team set out to learn the ultimate fate of the system by creating a model that allowed them to play ‘planetary pinball’ with the planets, researching what can cause the destabilization of the perfect rhythm.
They determined that the resonance that locks the four planets in place is expected to be sustained for the next 3 billion years, despite the effects of galactic tides and close flyovers of other stars. However, it still shatters once the star enters the phase in which it becomes a red giant, when it expands to several hundred times its current size and ejects nearly half of its mass, to finish in the form of a white dwarf.
The planets will then freak out and become a highly chaotic system where their movements become very uncertain. Even changing the position of a planet by one centimeter early in the process can drastically change the result.
Lead author Dr Dimitri Veras from the Department of Physics at the University of Warwick said: “The planets will disperse by gravity from each other. In one case, the innermost planet could be thrown out of the system. Or, in another case, the third planet may or the second and fourth planets could change position. Any combination is possible with small adjustments.
“They are so big and so close to each other that the only thing keeping them in this perfect rhythm right now are the locations of their orbits. All four are connected in this chain. As soon as the star loses it. mass, their locations will deviate, and then two of them will disperse, causing a chain reaction among the four. “
Dr Veras was supported by an Ernest Rutherford Fellowship from the Science and Technology Facilities Council, part of UK Research and Innovation.
Regardless of the precise movements of the planets, one thing the team is certain of is that the planets will move enough to dislodge matter from the system’s debris disks in the star’s atmosphere. It is this type of debris that astronomers are analyzing today to uncover the stories of other white dwarf systems.
Dr Veras adds, “These planets move around the white dwarf in different places and can easily throw any debris still present in the white dwarf, polluting it.
“The HR 8799 planetary system represents a taste of the polluted white dwarf systems we see today. It is a demonstration of the value of calculating the fate of planetary systems, rather than just looking at their formation.”
Co-author Professor Sasha Hinkley of the University of Exeter said: “The HR 8799 system has been so iconic for exoplanetary science since its discovery almost 13 years ago, and so it is fascinating to see the future and watch it evolve from a harmonious collection of planets into a chaotic scene. “
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