James Webb Space Telescope (JWST) may have found evidence of the universe's earliest stars, notably in the distant galaxy GN-z11. Collaborative efforts between NASA, and the European, and Canadian space agencies fuel this groundbreaking research and delve into the mysteries of this galaxy.
Existing just 430 million years after the Big Bang, researchers identified a crucial cluster of helium in its halo. The study, titled "JWST-JADES. Possible Population III signatures at z=10.6 in the halo of GN-z11" available in the preprint server arXiv and will be published in Astronomy & Astrophysics, could mark a significant milestone in contemporary astrophysics.
GN-z11's Extraordinary Journey Through Time with the JWST
Discovered by Hubble in 2015, GN-z11 was once the most remote galaxy and holds relevance due to its age, emerging 430 million years post-Big Bang. With a redshift of 10.6, it challenges predictions based on the standard cosmological model amidst its unique luminosity.
As a result, the JWST, equipped with near-infrared instruments like the Near-Infrared Camera (NIRCam) and the Near-Infrared Spectrometer (NIRSpec), has focused on GN-z11 as a prime subject for study.
Led by Roberto Maiolino from the University of Cambridge, an astronomy team utilized these instruments to explore GN-z11, uncovering compelling evidence of the first generation of stars known as Population III stars. Additionally, the observations unveiled a supermassive black hole voraciously consuming vast amounts of matter and experiencing accelerated growth.
The age of stars is determined by their heavy element abundance, derived from previous generations of stars that released these elements into space. Younger stars, formed in the last five or six billion years, are classified as Population I stars and boast a high heavy element abundance, while older stars with fewer heavy elements are categorized as Population II stars.
The notion of Population III stars, purely theoretical until now, gains empirical support through the JWST's revelations in GN-z11. These stars are believed to be the first stars, forming without predecessors.
They held no heavy elements, consisting solely of pristine hydrogen and helium from the Big Bang. They are believed to be highly luminous, possibly possessing masses equal to several hundred suns.
Probing Population III Stars in GN-z11 with Webb's Infrared Insight
Although direct observation of Population III stars remains elusive, Maiolino's team identified indirect signals in GN-z11, detecting a cluster of ionized helium using NIRSpec. The exclusive presence of helium implies a pristine environment, aligning with theoretical expectations of pockets of pristine gas near massive early galaxies.
Stars' cores serve as elemental factories, generating crucial elements like carbon, dispersed through supernova explosions. The ionization of helium in GN-z11 indicates a potent source of ultraviolet light, likely emanating from Population III stars.
The observed helium may constitute remnants from their formation, with the required luminosity suggesting early galaxies were more adept at producing massive stars than contemporary ones.
In astronomy, the ability to observe distant phenomena corresponds to glimpsing the past, as light and radiation take time to reach us. Webb's infrared capabilities enable it to penetrate space dust, providing a window into the universe's nascent stages.
The mission's primary goal is to witness the emergence of the first stars and galaxies, capturing the transformative moment when the cosmos experiences its inaugural illumination.
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