Dust from dead earthy planets found in atmosphere white dwarfs

The dust of dead earthy planets has been observed in the atmosphere of four nearby white dwarfs, the core of a dead star comparable to that of our sun.

A team from the University of Warwick has found outer layers containing up to 300,000 gigatons of rocky debris, containing up to 60 gigatons of lithium and 3,000 gigatons of potassium.

Researchers have also found traces of sodium and calcium, suggesting that the remains came from dead planets with similar crusts to those found on Earth and on Mars.

The discovery is not only the first time that astronomers have observed planetary crusts in the atmosphere of white dwarfs, but it also reveals that solar systems like ours have existed for billions of years.

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White dwarfs form after stars, like our own sun, deplete their nuclear fuel.

Towards the end of nuclear combustion, the star expels most of its outer material, creating a planetary nebula, which is a shell of gas and dust.

Here the star becomes a red giant and eventually a white dwarf.

During the process, however, the star can obliterate everything and everything around it.

The team, led by the University of Warwick, analyzed data from the Gaia Telescope of the European Space Agency (ESA) of more than 1,000 nearby white dwarf stars when they came across an unusual signal from one specific white dwarf.

Using a spectroscopy, the team analyzed the light from each star at different wavelengths.

It detected the detection of elements that may be hiding in the star’s atmosphere.

Scientists also inspected the 30,000 white dwarf spectra of the Sloan Digital Sky Survey published over the past 20 years.

The signal corresponds to the wavelength of lithium and astronomers soon discover three more white dwarfs with the same signal, one of which was also observed with potassium in its atmosphere.

It is believed that the four white dwarfs burned out their fuel until ten billion years ago and may be one of the oldest white dwarfs in our galaxy.

By comparing the amount of lithium and potassium with the other elements they detected – sodium and calcium – they found that the ratio of elements corresponds to the chemical composition of the crust of rocky planets such as Earth and Mars, as the crusts evaporate and are mixed. the gaseous outer layers of the star for 2 million years.

Chief author, dr. Mark Hollands, of the Department of Physics at the University of Warwick, said: “In the past we have seen all sorts of things like mantle and nuclear material, but we have not yet experienced a definite detection of planetary crust.”

“Lithium and potassium are good indicators of crusty material, but they are not in high concentrations in the mantle or core.”

‘Now that we know what chemical signature to detect these elements, we have the opportunity to look at a large number of white dwarfs and find more of them. Then we can look at the distribution of the signature and see how often we detect these planetary crusts and how they compare to our predictions. ‘

The amount of crust material orbiting the four stars is about the same mass as asteroids observed in our own solar system.

This information has led astronomers to suggest that vaporized crusts have broken down from a planet and are not the remnants of an entire planet.

“As we understand it, the formation of rocky planets takes place in the same way in different planetary systems,” said Dr. Holland said.

Initially it is formed from similar material composition as the star, but over time the materials separate and you get different chemical compositions in different parts of the planets. ‘

“We can see that the objects are differentiated at a stage where the composition is different from the initial composition of the star.”

“It is now well understood that most normal stars are like the Sun planets, but now there is also the opportunity to look at the frequency of different types of material.”