James Webb Space Telescope: "First real proof" for the first generation of stars
Black holes that were far too large shortly after the Big Bang posed a puzzle for astronomy. Now, stars were discovered that are said to have made them possible
Simulated representation of the birth of a supermassive black hole from the remnants of one of these "monster stars"
(Image: Nandal et al)
A research group has discovered the first traces of "monster stars" with the James Webb Space Telescope, which have between 1.000 and 10.000 solar masses and could solve a puzzle in astronomy. The University of Portsmouth, from where the research was led, has made this public. According to this, these supermassive stars are likely to be the precursors of particularly massive black holes that appeared unexpectedly early in the universe. These stars therefore belong to the so-called Population III. This is the designation for the first generation, which consisted only of the light elements hydrogen and helium available after the Big Bang, as well as small amounts of lithium. Those responsible believe they have solved a 20-year-old cosmic mystery.
The dinosaurs of the cosmos
The certainty of the research group is therefore based on the chemical composition of a galaxy called GS 3073, which we see in a state it assumed less than a billion years after the Big Bang. The ratio of nitrogen to oxygen determined there cannot be explained by any stellar explosion known to us, the team writes. Instead, it only fits primordial stars that were significantly more massive than our sun. These are said to have shone for only about 250.000 years before collapsing into extremely massive black holes. Thus, they were "enormously large and primitive" like dinosaurs, says co-author Daniel Whalen from the English university.
Further analyses have shown that these stars must have neither less than 1000 solar masses nor more than 10.000. Otherwise, they could not produce the observed signatures. They would burn helium in their core, producing carbon that escapes into the shell. With the hydrogen burning there, nitrogen would be produced, and the enriched material would then escape into space, enriching the surrounding gas. The team has now observed this excess nitrogen and is convinced that the space telescope will find further examples. In recent months, the presumed discovery of Population III stars has been announced several times.
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Since the space telescope began its research in the summer of 2022, discoveries of unusually early and unexpectedly massive black holes have caused consternation. Based on existing models of the universe's development, their existence could not be satisfactorily explained. The excess nitrogen in GS 3073, now presented in a scientific paper in the Astrophysical Journal Letters, and the explanation provided for it are now intended to solve the puzzle. The team writes that it is the "first conclusive evidence for the existence of supermassive Population III stars."
(mho)
