Astronomers led by the University of Warwick (UW) in the UK have identified a strange blue white dwarf named WDJ1922+0233, 9 billion years old, which is contaminated by planetary debris with a composition similar to Earth’s continental crust. . This shows that a star, similar to the Sun in its early days, devours planets orbiting it, very similar to Earththat lived and died billions of years before the solar system formed, communicated Recently.

Astronomers are also looking closely at another cold, dying white dwarf called WDJ2147-4035. It turned out to be the dimmest and reddest star found to date in the local galactic neighborhood, located 90 light years from Earth. They define it Its age is about 10.7 billion years. and its spectra reveal increasing concentrations of sodium, lithium, potassium, making it the oldest white dwarf contaminated with metals ever discovered.

The remnants found in the star’s atmosphere are from an ancient planetary system that turned into a white dwarf, allowing astronomers to assert that this is the oldest planetary system found around a white dwarf in the Milky Way. this result published logged in recently Monthly Notices of the Royal Astronomical Society.

“The red star WDJ2147-4035 is a mystery because the accumulated planetary debris is extremely rich in lithium and potassium and is unlike anything known in our solar system. This is a very interesting white dwarf because its icy surface temperature, the metals that contaminate it, its old age, and the fact that it is magneticthey make it incredibly rare,” said lead author Abbigail Elms of UW.

“This metal-contaminated star shows that Earth is not unique, there are other planetary systems that have bodies similar to Earth’s. 97% of all stars will be white dwarfs. […] Cool white dwarfs provide information about the formation and evolution of planetary systems around the oldest stars in the Milky Way,” comments Abbigail.

Professor Pier-Emmanuel Tremblay, from UW, explained what was unusual about the find: “When these old stars formed more than 10 billion years ago, universe it was less rich in metals than it is today, because metals are formed in evolving stars and giant star explosions. The two observed white dwarfs provide a fascinating window into planet formation in gas-rich, metal-poor environments that are different from the conditions under which the solar system formed.

Font: RT.