Astronomers have discovered the oldest star in the Milky Way

(ORDO NEWS) — Our Sun is about four and a half billion years old, and this figure seems huge. But astronomers have discovered a star that is more than twice as old.

Ultracool white dwarf WD J2147-4035 formed almost 10 billion years ago and is now just a tiny dot in the void of space surrounded by planetary debris.

The fate of most stars, including those like our Sun, is to become white dwarfs . A white dwarf is a star that has used up all of its hydrogen reserves and is now undergoing a cooling process.

During it, all the planets revolving around the star will gradually collapse.

This is the fate that befell a binary star system 90 light years from Earth. It was discovered by the Gaia space telescope of the European Space Agency.

Despite the name “white dwarfs”, one of the stars turned out to be an unusual blue hue, and the second – the dimmest and reddest of all discovered within our galaxy.

Scientists from the University of Warwick (UK) determined that the age of the red WD J2147-4035 is about 10.7 billion years. Curiously, the star was active for only half a billion years, after which it began to cool.

An analysis of the emitted light at different wavelengths made it possible to determine the composition of the elements in the star’s atmosphere.

There were unexpectedly many heavy elements – sodium, lithium, potassium and carbon, which got there along with planetary debris.

The second star WDJ1922+0233 turned out to be only slightly younger than its neighbor, its age was determined at nine billion years.

Its surface also turned out to be “littered” with fragments of planets, similar in composition to the continental crust of the Earth.

Perhaps the star’s unusual color is due to its helium-hydrogen atmosphere. WD J2147-4035 has an almost pure helium atmosphere.

In addition to their age, the two white dwarfs are also the coldest stars observed, both of which have an effective temperature of less than 3,000 degrees Celsius.

For comparison, the Sun has more than 5500 degrees.

Although the planets of this star system resembled the Earth in composition, they formed six billion years before it. Probably, celestial bodies of this type are not uncommon in our Galaxy.

The study of such dwarfs allows astronomers to “look into the past” by studying the chemical composition of celestial bodies that formed, erupted and died long before the appearance of our solar system.


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