Important discovery in a strange galaxy – “Needles plucked from haystacks”

Researchers make a special discovery in the Large Magellanic Cloud: a second-generation star. It's an important idea for astronomy.

CHICAGO – Man and everything around him is made of stardust. What sounds metaphorical is actually what astronomers believe to be literal: the matter from which everything is created comes from the first stars in the universe. When they died, they exploded and the elements made of hydrogen and helium inside them were dispersed into space. This not only gave rise to new stars, but in the long run also gave rise to the Earth and everything on it.

So far, no stars of this first generation have been found in space. But it appears that a research team has now succeeded in tracking down a second-generation star in another galaxy. “This star provides a unique insight into the very early process of element formation in galaxies other than our own,” says Anirudh Chetty of the University of Chicago, lead author of the paper. In the specialized magazine Nature astronomywhich displays the search results.

Research team finds second-generation star in another galaxy

The star discovered by Chetty and his team is located in the Large Magellanic Cloud, a satellite galaxy of the Milky Way that was captured by our Galaxy's gravity several billion years ago. “We want to understand what the properties of the first stars were and what elements they produced,” explains Chetty, who specializes in stellar archaeology, a field that studies the oldest generations of stars and wants to know how they changed the universe.

Because no one knows whether first-generation stars still exist, Chetty and his team searched for stars that emerged from the “ashes” of the first generation. These stars are now incredibly old and rare. Most stars in the universe – including our Sun – are many generations younger than the second generation of stars. “Perhaps less than one star out of every 100,000 stars in the Milky Way is a second-generation star,” Chetty points out. “You really are like fishing needles out of haystacks.”

Ancient stars provide insight into the universe's past

But it's worth tracking down ancient stars because they can provide good insight into the universe's past, Chetty explains: “In their outer layers, these stars preserve elements near where they were formed. If you find a very old star and can determine its chemical composition, you can Understanding the chemical composition of the universe when this star formed billions of years ago.

With the help of the European Space Agency's Gaia space probe and the Magellan Telescope in Chile, the research team searched for very ancient stars in the Large Magellanic Cloud. They discovered ten of them, and one stood out because it contained far fewer heavy elements than all the other stars in the satellite galaxy. Because the star is assumed to have formed from the first generation of stars, it has not yet had the opportunity to form heavier elements.

The star is clearly distinguished from the stars of the Milky Way

“We have an idea of ​​what these stars, chemically rich as the first stars, look like in the Milky Way, but we don't know yet whether some of these signatures are unique or whether things have happened similarly in other galaxies,” Chetty says in one notice. But in the course of the study, his research team discovered serious differences between ancient stars in the Milky Way: compared to the stars of the Milky Way, the star contains much less carbon than iron.

“This was very interesting, and suggests that the accumulation of carbon in the first generation, as we see in the Milky Way, may not have been global,” Chetty explains. He continued: “We need to conduct more studies, but they indicate that there are differences from one place to another.” “This discovery indicates that there must be many such stars in the Large Magellanic Cloud if we look closely.” (unpaid bill)