Dust from dead Earth-like planets has been observed in the atmosphere of four nearby white dwarfs, the core of a dead star similar to that of our sun.
A team from the University of Warwick found outer layers containing up to 300,000 gigatons of rocky debris, including up to 60 gigatons of lithium and 3,000 gigatons of potassium.
Researchers also found traces of sodium and calcium, suggesting the remains are from dead planets with similar crusts to those on Earth and Mars.
The discovery is not only the first time that astronomers have witnessed 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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Astronomers found outer layers containing up to 300,000 gigatons of rocky debris, including up to 60 gigatons of lithium and 3,000 gigatons of potassium. Researchers also found traces of sodium and calcium
White dwarfs are formed after stars, like our own sun, have exhausted their nuclear fuel.
Towards the end of its nuclear combustion, the star ejects most of its outer material, creating a planetary nebula, an envelope of gas and dust.
Here the star becomes a red giant and finally a white dwarf.
However, in the process, the star can erase anything and everything around it.
The discovery is not only the first time that astronomers have witnessed planetary crusts in the atmosphere of white dwarfs (stock), but it also reveals that solar systems like ours have existed for billions of years.
The University of Warwick-led team analyzed data from the European Space Agency’s (ESA) Gaia telescope of more than 1,000 nearby white dwarf stars when they encountered an unusual signal from a particular white dwarf.
Using spectroscopy, the team analyzed the light from each star at different wavelengths.
This allowed for the detection of elements that may be lurking in the star’s atmosphere.
Scientists also inspected the Sloan Digital Sky Survey’s 30,000 white dwarf spectra published over the past 20 years.
The signal matched the wavelength of lithium, and the astronomers soon discovered three more white dwarfs with the same signal, one of which was also observed with potassium in its atmosphere.
By comparing the amount of lithium and potassium with the other elements they discovered – sodium and calcium – they found that the ratio of the elements matched the chemical composition of the crust of rocky planets such as Earth and Mars (photo)
The four white dwarfs are believed to have burned out their fuel up to 10 billion years ago and may be among the oldest white dwarfs formed in our galaxy.
By comparing the amount of lithium and potassium with the other elements they discovered – sodium and calcium – they found that the ratio of the elements matched the chemical makeup of the crusts of rocky planets like Earth and Mars, when those crusts had evaporated and mixed in. the gaseous outer layers of the star for 2 million years.
Lead author Dr. Mark Hollands of the University of Warwick’s Department of Physics said, “In the past we’ve seen all sorts of things like mantle and nuclear material, but we haven’t had a definitive detection of planetary crust.”
‘Lithium and potassium are good indicators of crust material, they are not present in high concentrations in the mantle or core.’
Now that we know what chemical signature to look for to detect these elements, we have the ability to look at a large number of white dwarfs and find more of them. Then we can look at the distribution of that signature and see how often we detect these planetary crusts and how that compares to our predictions. ‘
The amount of crustal material discovered orbiting the four stars is about the same weight as asteroids observed in our own solar system.
This information led astronomers to suggest that a planet’s evaporated crusts have broken off and are not the remains of an entire planet.
“As we understand it, the formation of rocky planets takes place in a similar way in different planetary systems,” said Dr. Holland.
Initially they are formed from a similar material composition to the star, but over time those materials separate and you get different chemical compositions in different parts of the planets. ‘
“We can see that these objects have undergone differentiation at some point, in which the composition differs from the star’s starting composition.”
“It is now clear that most normal stars, such as the Sun, harbor planets, but now there is the possibility to also look at the frequency of different types of material.”
WHAT HAPPENS TO THE EARTH WHEN THE SUN DIES?
In five billion years, the sun would have grown into a red giant star, more than a hundred times larger than its current size.
Ultimately, it will emit gas and dust to create a ‘shell’ that accounts for as much as half of its mass.
The nucleus becomes a small white dwarf star. This will shine for thousands of years, illuminating the envelope to create an annular planetary nebula.
In five billion years, the sun would have grown into a red giant star, more than a hundred times larger than its current size (photo file)
While this metamorphosis will change the solar system, scientists are not sure what will happen to the third stone from the sun.
We already know that our sun will be bigger and brighter, so it will likely destroy every form of life on our planet.
But whether Earth’s rocky core will survive is uncertain.