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Universe: If the star HR 8799 dies, a giant "space fin" is created

Universe: If the star HR 8799 dies, a giant “space fin” is created

  • toTanya Banner


Researchers have discovered that the synchronous dance of unusually large planets will likely end in chaos one day. You would expect some kind of “space fin”.

Frankfurt – The planetary system around the star HR 8799 in the constellation Pegasus is remarkable: four unusually large planets orbit the star, which is 30-40 million years old. Planets HR 8799 b, c, d, and e have at least five times the mass of Jupiter and are very close to each other in their orbits around the star. Studies show that planets dance around their star in a perfect rhythm: while the outer planet completes its orbit once, the neighboring planet orbits the star exactly twice. Its inner neighbor orbits the star four times at the same time, while the nearest planet orbits the star exactly eight times. But one day the synchronous motions of the planetary system around the star HR 8799 will end.

Researchers from the Universities of Warwick and Exeter have analyzed what happens when a star at the center of the system dies and becomes a white dwarf. realizing that you are In the monthly notifications of the Royal Astronomical Society veröffentlicht have: If the star HR 8799 dies, the synchronous planets become a kind of “space fin”. The planets will then be thrown out of their orbits and bounce off other planets’ gravity, “like balls bouncing off a ring during a pinball game,” according to a statement from the researchers.

A look at the universe: the simultaneous chaos of four planets will end one day

According to the research team’s calculations, the simultaneous dance of the four planets will continue for the next 3 billion years. But as soon as the star in the center of the system begins to turn into a red giant, the synchronization ends: the star swells to several hundred of its current size and loses about half its mass before turning into a white dwarf star. . The planetary pinball machine begins. “The planets are gravitationally scattered from each other,” explains lead author Dmitri Veras. “In one case, the innermost planet could be ejected from the system. Or in another case, the third planet could be ejected. Any combination is possible, including the fact that the second and fourth planets exchange positions.”

HR 8799 System: From Synchronous Planetary Dance to “Space Pinball”

“They’re so big and so close together — the only thing currently keeping them in their perfect cadence are their orbits,” Veritas confirms. “The four are connected in this chain. Once the star loses its mass, its positions are skewed, and the two of them will repel each other and start a chain reaction between the four planets.”

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The researchers wrote in their study that over time, the planetary system should become very chaotic. The movements become unpredictable, if the position of the planet is changed by only one centimeter when the process begins, then everything will change.

HR 8799 and its planets are important for exoplanet research

Three of the planets orbiting the star HR 8799 were discovered in 2008 with the help of the Keck and Gemini telescopes, the innermost planet was discovered in 2009, and three of the planets were later discovered in the images taken by the Hubble Space Telescope in 1998. Since 2016, the presence of a fifth planet has been assumed in the system, but it has not yet been verified. NASA recently discovered another exciting planet.

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“The HR 8799 system has been ingenious for exoplanet research, so it’s fascinating to look into its future and see how it evolves from a harmonious set of planets to a chaotic landscape,” says co-author Sasha Hinckley. But there’s a simple reason: the researchers won’t see if their predictions will actually come true in the distant future. (Tania Banner)