ESO: Distant Gas Clouds with Leftovers of the First Stars

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ESO: Distant Gas Clouds with Leftovers of the First Stars

Post by bystander » Wed May 03, 2023 4:45 pm

Astronomers Find Distant Gas Clouds with Leftovers of the First Stars
ESO Science Release | 2023 May 03
Using ESO’s Very Large Telescope (VLT), researchers have found for the first time the fingerprints left by the explosion of the first stars in the Universe. They detected three distant gas clouds whose chemical composition matches what we expect from the first stellar explosions. These findings bring us one step closer to understanding the nature of the first stars that formed after the Big Bang. ...

Researchers think that the first stars that formed in the Universe were very different from the ones we see today. When they appeared 13.5 billion years ago, they contained just hydrogen and helium, the simplest chemical elements in nature. These stars, thought to be tens or hundreds of times more massive than our Sun, quickly died in powerful explosions known as supernovae, enriching the surrounding gas with heavier elements for the first time. Later generations of stars were born out of that enriched gas, and in turn ejected heavier elements as they too died. But the very first stars are now long gone, so how can researchers learn more about them? ...

Using data taken with ESO’s VLT in Chile, the team found three very distant gas clouds, seen when the Universe was just 10–15% of its current age, and with a chemical fingerprint matching what we expect from the explosions of the first stars. Depending on the mass of these early stars and the energy of their explosions, these first supernovae released different chemical elements such as carbon, oxygen and magnesium, which are present in the outer layers of stars. But some of these explosions were not energetic enough to expel heavier elements like iron, which is found only in the cores of stars. To search for the telltale sign of these very first stars that exploded as low energy supernovae, the team therefore looked for distant gas clouds poor in iron but rich in the other elements. And they found just that: three faraway clouds in the early Universe with very little iron but plenty of carbon and other elements — the fingerprint of the explosions of the very first stars. ...

Evidence of First Stars-Enriched Gas in High-Redshift Absorbers ~ Andrea Saccardi et al
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