Astronomers managed to see the death of another star system

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Astronomers managed to see the death of another star system
Astronomers managed to see the death of another star system
Anonim

There are many mysteries drifting in the cosmic ocean, the existence of which we do not even know. One of these was discovered five years ago, when astronomers discovered a lone star at a distance of 570 light years from Earth, the brightness of which dimmed irregularly every 4.5-5 hours. After close examination, it turned out that this is a white dwarf "WD 1145 + 017", which engulfs the planets of its system. The discovery marked the beginning of necroplanetology - perhaps the most unusual field of astronomy, which studies the fate of already dead planets. Like fantasy necromancers, astronomers resurrect dead planets in order to find out about their past, trying to simulate what these distant worlds were like, what they consisted of and how they influenced other objects in their star system. Moreover, the study of such planets can tell a lot about the death of the star systems themselves.

What is necroplanetology and how did it come about?

WD 1145 + 017 is a star in the constellation Virgo. Distance from Earth is about 570 light years. This means that what we see now through telescopes happened to the star 570 years ago. Travel to the past, not otherwise!

In 2015, astronomers noticed that WD 1145 + 017 was dimming at an irregular rate, and after closer examination, they realized that the star was devouring planets in its solar system through a process called a burst of tidal destruction - when a star approaches the event horizon of a supermassive black hole and tears it apart. tidal forces, by "spaghettification". For more information on what it is and why if you fall into a black hole, you will also turn into spaghetti, read our material. Remarkably, it took five years for the study to be accepted for peer review in The Astrophysical Journal. All this time, the work was in the public domain on the preprint server in arXiv.

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White dwarfs look like this

White dwarf - in simple words, it is a star devoid of sources of thermonuclear energy. In fact, it just cools and dims, like a recently turned off burner on an electric stove.

Just before going supernova or black dwarf, dying stars become white dwarfs. Such a fate awaits our Sun, but fortunately, not earlier than in six billion years. White dwarfs lack sources of thermonuclear energy and glow weakly, gradually cooling and turning red. The atmospheres of such stars usually contain lighter elements such as helium and hydrogen. It was thanks to the study of the atmosphere of WD 1145 + 017 that astronomers realized that the white dwarf they discovered behaves somewhat unusual: the brightness of the star decreased by different values every 4.5-5 hours, and traces of elements that are usually found in the cores of rocky planets - iron, oxygen and magnesium.

To figure out how the planets met their doom, the researchers created a series of computer simulations that showed how 36 different types of planets would react to being swallowed up by their home star. The results showed that most often it was rocky planets that withstood the main stage of destruction, but disintegrated within a short period of time. It is important to understand that all the described processes lasted thousands of years. The reason that no small objects were found around the white dwarf WD 1145 + 017 is that all the debris of the planets is absorbed by the monstrous force of gravity. The remnants of the planets lose mass and shape - for this reason, the brightness of the star dims.

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Studying the remains of rocky planets, you can unravel the secrets of galaxies and the Universe

Thus, necroplanetology kills two birds with one stone - with its help, scientists can simultaneously study the death of white dwarfs and planets, gradually restoring the chronology of events and how the evolution of stellar systems occurs. So, last year alone, more than 20 dying stellar systems were discovered, in each of which the remains of the dead planets store the most valuable information. This became possible because astronomers explained the similar behavior of other stars, which in the past caused heated debate in the academic environment. It turned out that the stars were just dead, and the surrounding space bodies, formed by gravity, created the effect of darkening the glow.

So, studying the remains of the dead planets, researchers will learn about their rate of destruction. In the future, the restoration of their previous appearance will allow modeling entire stellar systems in which these distant worlds were born, as well as a glimpse into the past of galaxies. Ultimately, a series of future discoveries will allow us to better understand the structure of our universe. By the way, despite its name, the field of necroplanetology is flourishing today and this cannot but rejoice.

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