Lost Alien Civilizations? Vaporized Crusts of Earth-like Planets Found in Dying Stars

Remnants of planets with Earth-like crusts have been discovered in the atmospheres of four nearby white dwarf stars by University of Warwick astronomers, offering a glimpse of the planets that may have once orbited them up to billions of years ago.

 

These crusts are from the outer layers of rocky planets similar to Earth and Mars and could give astronomers greater insights into the chemistry of the planets that these dying stars once hosted.

The discovery is reported today in the journal Nature Astronomy and includes one of the oldest planetary systems seen by astronomers so far.

 

The University of Warwick-led team were analyzing data from the European Space Agency’s Gaia telescope of over 1,000 nearby white dwarf stars when they came across an unusual signal from one particular white dwarf. The researchers at the University of Warwick received funding from the European Research Council and the Science and Technology Facilities Council (STFC).

 

They used spectroscopy to analyze the light from the star at different wavelengths, which allows them to detect when elements in the star’s atmosphere are absorbing light at different colors and determine what elements those are and how much is present. They also inspected the 30,000 white dwarf spectra from the Sloan Digital Sky Survey published over the last 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 detected—sodium and calcium—they found that the ratio of elements matched the chemical composition of the crust of rocky planets like Earth and Mars, if those crusts and been vaporized and mixed within the gaseous outer layers of the star for 2 million years.

Read the full article at: phys.org