For the first time, astronomers have found what they describe as “fingerprints” left by the explosions of the first stars in the universe in three distant clouds.
The first generation of stars made it possible for the universe to have the building blocks of planets and ultimately life. These objects consisted only of hydrogen and helium and were hundreds of times larger than the Sun. They burned brightly and went supernova very quickly (for the universe). Therefore, we have never been able to directly observe these entities.
However, despite their elusive nature, the work to find traces of these beings is in full swing, and astronomers are now reporting that they have found the best evidence of the aftermath of the first stellar explosions. Gas clouds in the distant universe have the right chemical composition to indicate that they may be the product of the death of the first stars.
“For the first time, we have been able to detect chemical traces of the explosions of the first stars in very distant gas clouds,” Andrea Saccardi, a doctoral student at the Observatoire de Paris-PSL, who led the study during her master’s thesis at the University of Florence, said in a statement.
After the big bang, only the lightest elements could form in a stage called nucleosynthesis. These elements were hydrogen and helium, along with very small amounts of lithium. The remaining elements arose by nuclear fusion in the cores of stars or by other stellar events, including supernovas.
Astronomers study the influence of early stars indirectly by looking at the composition of some of the oldest stars in our galaxy, which are believed to have formed from the “ashes” of the first stars. This study shows that it is possible to find “ashes” directly.
“The first stars can be studied indirectly by detecting the chemical elements they emit after their death,” says Associate Professor Stefania Salvadori of the University of Florence. ”
The research team used the Very Large Telescope to find these clouds, which exist for the first 10-15 percent of the universe’s life. Although this percentile was much later than the explosion of the first stars, the clouds that formed were not yet polluted. The team used the light of even more distant quasars behind these clouds to illuminate them and allow the researchers to decipher their chemical composition. For example, the first stars are not expected to release much iron.
The three clouds studied, while rich in elements such as carbon and magnesium, were poor in iron, suggesting they were enriched with materials from early stars.
The study was published in The Astrophysical Journal.
58008
