Astronomers discover oldest known star in the galactic halo
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Loading... - Arif Siregar
- 08 Jun 2023
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An international team of researchers has made a remarkable finding by uncovering the most ancient star known to exist in the galactic halo. The star's origins can be traced back to a gas cloud that was left behind by a first-generation star, boasting a colossal mass of up to 260 times that of our sun.
This groundbreaking discovery has significantly advanced humanity's comprehension of the initial stars and the evolution of both the Milky Way and the universe as a whole.
Recently published in the esteemed scientific journal Nature on June 7, the study was spearheaded by a group of Chinese astronomers hailing from the National Astronomical Observatories of China (NAOC), which operates under the umbrella of the Chinese Academy of Sciences (CAS).
Zhao Gang, the head of the research project, explained that the first stars illuminated the universe during the cosmic dawn, effectively bringing an end to the cosmic "dark ages" that ensued after the Big Bang. Nonetheless, the distribution of their masses remains one of the enigmatic mysteries of the cosmos.
Through numerical simulations focused on the formation of initial stars, experts have estimated that these stellar entities could possess masses ranging up to several hundred times that of our sun. Within this range, stars with masses between 140 and 260 solar masses eventually undergo a distinctive type of supernova known as pair-instability supernovae (PISNe). This particular phenomenon leaves a distinct chemical imprint within the atmosphere of subsequent generations of stars, as elucidated by Zhao.
Nevertheless, concrete evidence supporting the occurrence of such supernovae had been absent until now.
Leveraging data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) in China and subsequent observations from the Subaru telescope in Japan, scientists successfully identified a chemically anomalous star dubbed LAMOST J1010+2358. Its unique chemical properties align perfectly with the characteristics anticipated from a PISN according to existing theories. Thus, researchers have confirmed that this star was formed within a gas cloud predominantly composed of remnants from a PISN boasting a staggering mass of 260 solar masses.
"This discovery represents the inaugural and unequivocal evidence of a PISN's existence, originating from an exceedingly massive first-generation star in the early universe," declared Xing Qianfan, a prominent member of the study from NAOC.
The revelation serves to substantiate the notion that the mass of initial-generation stars could indeed reach several hundred times that of our sun. Consequently, it will profoundly influence investigations into the origins of elements, star formation during the early stages of the universe, and the chemical evolution of galaxies, as emphasized by Zhao.
