May 5, 2024

Stellar “Ashes” – Astronomers Discover Traces of Universe’s First Stars

Minutes after the Big Bang the only elements present in deep space were the three lightest ones: hydrogen, helium and extremely little traces of lithium. Much heavier aspects were formed much later on in stars.

Using ESOs Very Large Telescope, astronomers have actually found three remote gas clouds whose chemical structure matches what we anticipate from the explosions of the first stars that appeared in the Universe. These early stars can be studied indirectly by evaluating the chemical elements they distributed into the surrounding environment after they passed away in supernova explosions. This is exactly the signature anticipated from the surges of the very first stars.
Using ESOs Very Large Telescope (VLT), scientists have actually discovered for the very first time the fingerprints left by the explosion of the first stars in the Universe. They detected 3 distant gas clouds whose chemical composition matches what we get out of the first stellar explosions. These findings bring us one action closer to understanding the nature of the very first stars that formed after the Big Bang.
” For the very first time ever, we were able to identify the chemical traces of the explosions of the first stars in really far-off gas clouds,” states Andrea Saccardi, a PhD trainee at the Observatoire de Paris– PSL, who led this study throughout his masters thesis at the University of Florence.
Researchers think that the first stars that formed in the Universe were very various from the ones we see today. These stars, thought to be tens or hundreds of times more huge than our Sun, rapidly died in powerful explosions understood as supernovae, enhancing the surrounding gas with heavier aspects for the first time. The extremely first stars are now long gone, so how can researchers discover more about them?

Utilizing ESOs Very Large Telescope, astronomers have actually discovered the finger prints left by the explosions of the very first stars. Credit: ESO
Utilizing data taken with ESOs VLT in Chile, the group found three very far-off gas clouds, seen when deep space was simply 10– 15% of its current age, and with a chemical finger print matching what we get out of the explosions of the very first stars. Depending upon the mass of these early stars and the energy of their explosions, these very first supernovae released different chemical elements such as carbon, oxygen and magnesium, which are present in the outer layers of stars. However some of these explosions were not energetic adequate to expel heavier components like iron, which is discovered just in the cores of stars. To search for the indication of these very first stars that exploded as low energy supernovae, the group therefore looked for far-off gas clouds poor in iron however rich in the other components. And they found simply that: three far clouds in the early Universe with very little iron however a lot of carbon and other components– the finger print of the explosions of the very first stars.
When the light of the quasar passes through the gas cloud, the chemical elements in it take in various colors or wavelengths, leaving dark lines in the spectrum of the quasar. Each aspect leaves a various set of lines, so by studying the spectrum astronomers can work out the chemical structure of the stepping in gas cloud.
This strange chemical structure has likewise been observed in numerous old stars in our own galaxy, which researchers think about to be second-generation stars that formed straight from the ashes of the first ones. This new study has actually found such ashes in the early Universe, therefore including a missing piece to this puzzle. “Our discovery opens new avenues to indirectly study the nature of the first stars, completely complementing studies of stars in our galaxy,” discusses Salvadori.
To spot and study these distant gas clouds, the group used light beacons called quasars– extremely intense sources powered by supermassive black holes at the centers of faraway galaxies. As the light from a quasar travels through the Universe, it goes through gas clouds where different chemical aspects leave an imprint on the light.
To find these chemical imprints, the group examined data on numerous quasars observed with the X-shooter instrument on ESOs VLT. X-shooter divides light into an incredibly large range of wavelengths, or colors, that makes it a special instrument with which to determine lots of various chemical components in these distant clouds.
This research study opens brand-new windows for next-generation telescopes and instruments, like ESOs upcoming Extremely Large Telescope (ELT) and its high-resolution ArmazoNes high Dispersion Echelle Spectrograph (ANDES). “With ANDES at the ELT we will be able to study a lot of these unusual gas clouds in higher information, and we will be able to lastly discover the strange nature of the first stars,” concludes Valentina DOdorico, a researcher at the National Institute of Astrophysics in Italy and co-author of the study.
Notes

This research was provided in a paper to appear in the Astrophysical Journal.
Reference: “Evidence of first stars-enriched gas in high-redshift absorbers” 3 May 2023, Astrophysical Journal.DOI: 10.3847/ 1538-4357/ acc39f.
The team is made up of Andrea Saccardi (GEPI, Observatoire de Paris, Université PSL, CNRS, France; Dipartimento di Fisica e Astronomia, University of Florence, Italy [UFlorence], Stefania Salvadori (UFlorence; INAF– Osservatorio Astrofisico di Arcetri, Italy), Valentina DOdorico (Scuola Normale Superiore, Italy; INAF– Osservatorio Astrofisico di Trieste, Italy [INAF Trieste]; IFPU– Institute for Fundamental Physics of the Universe, Italy [IFPU] , Guido Cupani (INAF Trieste; IFPU), Michele Fumagalli (Dipartimento di Fisica G. Occhialini, University of Milano Bicocca, Italy; INAF Trieste), Trystyn A. M. Berg (Dipartimento di Fisica G. Occhialini, University of Milano Bicocca, Italy), George D. Becker (Department of Physics & & Astronomy, University of California, USA), Sara Ellison (Department of Physics & & Astronomy, University of Victoria, Canada), Sebastian Lopez (Departamento de Astronomía, Universidad de Chile, Chile).

Utilizing ESOs Very Large Telescope, astronomers have found three distant gas clouds whose chemical structure matches what we anticipate from the surges of the very first stars that appeared in the Universe. Utilizing ESOs Very Large Telescope (VLT), researchers have discovered for the very first time the finger prints left by the surge of the very first stars in the Universe. Utilizing information taken with ESOs VLT in Chile, the team discovered three extremely far-off gas clouds, seen when the Universe was just 10– 15% of its current age, and with a chemical finger print matching what we anticipate from the surges of the very first stars. Depending on the mass of these early stars and the energy of their explosions, these first supernovae released various chemical aspects such as oxygen, magnesium and carbon, which are present in the outer layers of stars. “Our discovery opens new avenues to indirectly study the nature of the first stars, completely complementing research studies of stars in our galaxy,” discusses Salvadori.